kermit window

Not necessarily new , every now and then you'll get a comment from a years old account that does nothing but comment

Yes; that, and the fact that even other Kool-Aid supping leftists don't really like most leftist memes. Oh they 1000% AGREE with the party approved political propaganda; but even they tend to default to stuff that is amusing, if nothing else.

Because they are waaaaaaaaaay more often amusing as well as insightful and generally true in nature, this also explains why, in comparison, most conservative memes get way more points than leftist memes.

The level of their intelligence is also a factor

Yep; most likely it is all tied together.