Remove LifterLMS Mailchimp Consent Feature

llms-mailchimp-remove-consent.php

<?php // Do not copy this line

// Copy from under this line and paste into your child theme's functions.php

add_action( 'init', 'llms_mc_remove_consent' );

function llms_mc_remove_consent(){
	
	// remove the following line if you want to keep the consent form on checkout
	remove_action( 'llms_registration_privacy', 'llms_mc_consent_form_field' );
	
	// remove the following line if you want to keep the consent form on user's profile
	remove_action( 'lifterlms_after_update_fields', 'llms_mc_dashboard_consent_form_field' );
}

You forgot the hook priority, should be:

remove_action( 'llms_registration_privacy', 'llms_mc_consent_form_field', 15 );
remove_action( 'lifterlms_after_update_fields', 'llms_mc_dashboard_consent_form_field', 15 );

As of version 3.x you should use this instead:

add_filter( 'llms_mc_enable_consent', '__return_false' );