No it's not. I am at a lost to understand why people are so eager to propagate myths rather than just stick to describing reality.
Here, I ensured I am comparing apples with apples, i.e.
SAME LISTS, and I forced garbage collection on both extensions:
View attachment 18830
Settings:
View attachment 18831 View attachment 18832
And Adguard tags you with a unique id, and track your browsing history if you enable "Malware, phising protection". They changed their code to make it less obvious (no longer logged in console), but it's still all there, it can be seen from the dev network tab.
Edit: after I posted I realized I had forgotten to uncheck
"Activate the most appropriate filters automatically", so I did this, restarted the browser, and now I can't get better than this for Adguard, even after forcing garbage collection:
View attachment 18835
So for you to obtain the memory footprint shown in your thumbnail I strongly suspect it's because the setting
"Activate the most appropriate filters automatically" delays the loading of filters until Adguard has identified which filters are relevant to the user given what web pages they browse (language, or something). No too long after I posted, I received a notification from Adguard telling me it has selected the English filters, implying they were not parsed/enforced when I took my original screenshot. Now they seems parsed and enforced even if I deselected them.