UPDATED 22.11.2022
It's been two years since the last update, so here's the updated working script as per the comments below.
Thanks to BryanHaley for this.
setInterval(function () {
video = document.getElementsByTagName('ytd-playlist-video-renderer')[0];
video.querySelector('#primary button[aria-label="Action menu"]').click();
var things = document.evaluate(
'//span[contains(text(),"Remove from")]',
document,
null,
XPathResult.ORDERED_NODE_SNAPSHOT_TYPE,
null
);
for (var i = 0; i < things.snapshotLength; i++)
{
things.snapshotItem(i).click();
}
}, 500);
Non-english users will need to change "Action menu" and "Remove from" to what YouTube uses for their localization.
Sorry for the response time, changed accounts and didn't notice so many people are using the script 😀
If you still want to use my script in your extension that is completely fine, just post it under a libre license like GPL or MIT.