Part of what you seem to try to contextualize has to do with historical thinking and specifically if you should or shouldn't apply modern values to historic events and people. Which is a valid question and something that also depends on how you are looking at history and for what purpose. If you are studying history and are trying to understand events as they unfolded it can sometimes hinder you to apply your modern values directly as they will prevent you from understanding why things happen at that time. That doesn't however mean that you can't judge actions of historical people for being wrong compared to today's standards.
To give some context I did grab a book from my book shelve which is aimed at aspiring history teachers as it goes into didactic challenges involved in teaching history as it has a relevant passage in it. Unfortunately the book is in dutch so I did my best to translate it.
A history teacher confronts his pupils with a situation in which a lord kills three serfs on his own domain and three on the domain of his neighbour. What was worse now? Or was it both equally bad? One student answers: "It's worse to kill your neighbor's serfs... "But it's three people on both domains, isn't it? The pupil says: 'Yes, but in the past serfs were considered property. It's worse if you destroy someone else's property than your own.
This student is in a way 'good at history'. He assesses the situation from the value pattern of the past and thus thinks historically. But he comes to a conclusion that sounds very strange to us. In our opinion a human being is simply not a thing and it is therefore difficult for us to hear the pupil talk in terms of 'destroying things'. Such a kind of clash of values and related modes of judgement is closely related to historical thinking. The way in which a distinction is made between what is good and what is evil depends on the value pattern of the culture of which one is part.
Historical thinking has an eye for the unique value patterns of each culture, of each era. No value pattern is then universal or universally valid; every value pattern is historically determined.
If every time and culture has its own value pattern, this means that every time must also be judged 'from within'.
It is not acceptable to measure other times by the measure of one's own time. If one does, then one would implicitly claim that the value pattern of one's own time is superior to value patterns from other times or cultures. The only thing a historian has to do according to these beliefs is to describe developments and explain why things turned out the way they did, without judging.There is, however, a catch. When explaining developments value patterns will also have to be involved.
If, for example, one wants to explain why Jews were persecuted and exterminated during the Nazi regime, the value pattern of a racist ideology will have to be involved. According to this value pattern, murdering 'inferior races' was a good thing; it is therefore explainable that it happened. If one leaves it at such an explanation, it creates the appearance of justification. After all, according to the value pattern at the time, it was 'logical' that genocide was committed. Nevertheless, as teachers we would not be satisfied if that were the only conclusion pupils would draw from the history of the Holocaust.
Perhaps here we come up against the limits of historical thinking. Is insight into the relativity and changeability of value patterns really good for anything? Although taking a stand with its own contemporary norms and values always remains important, history education can play an important corrective and nuancing role in this. This will lead to a tendency to be less rigid in distinguishing between good and evil. The previously discussed relativization of one's own beliefs and the sense of historical boundness (and thus potential variability) thereof are part of this. Mild judgment, understanding of circumstances, greater tolerance for the other, less sharpening and less irreconcilability of opposites could be the fruits of a skilled historical posture.
And a bit further it goes into it as well.
All this influences the way we judge the past. On the one hand we have to take into account what was considered normal in another time, on the other hand we can only judge with our own standards. Just 'understanding' what used to happen without our own judgement soon gives the added flavour of 'approving everything'. But just rejecting everything from the past with the standards of our own time is not possible either. In history, this dilemma is known as the tension between understanding and judging.
As the book itself says there are some catches involved and it is a challenging subject to begin with. What I personally think is important is making clear in which context you are looking at history. And the biggest takeaway for me personally always has been that it is possible to understand why things did play out like they did and understand why people acted like they did without agreeing with it personally. The latter is something that many people struggle with in my experience and where often (certainly on reddit) people conflate someones explanation for events at the time for that person agreeing with the same events.
In case some dutch people wander by and are interested this is the book in question.
In addition to this there is also the simple fact that the more recent something has happend the more we know about it generally speaking which gives us more information to look at a person or an event. Part of that information is also living memory that comes into account. The actions of Romans don't have a direct impact on living history or even as much on modern society in that regard where there are still people alive today who have directly experienced the impact of Churchil's decisions which possibly makes it all the more important to look at them.
It also is incidentally why we in this subreddit have a 20 year rule, not because history starts 20 years ago but because any more recent and it becomes near impossible to look at things historically as it becomes very much personal for many people. Less an issue in academic circles although also there you'll find lively debate about how objective you can study recent history a nice book to read in that aspect is "History and the Historians" which goes deeper into how history has been recorded over the centuries with different goals and philosophies.
So to put it rather directly, it might be possible that what you say is true. But at the same time that doesn't mean that the same information isn't relevant now and as I said earlier it can also simply be the lack of information available to us for more ancient events.
In that regard you do have to be aware that just because it might be so in the future doesn't mean that it isn't important or relevant today.