Like I've said in other streams that talk about this issue, memes don't always have to be funny, per the thesaurus definition.
They can be PSAs, reflections, ruminations, etc.
Thought-provoking may be provoking for some who haven't thought about the subject previously whereas others may find it something worthy to scroll past.
I agree some memes, for my taste, are kinda dry. But to say that "the left can't meme" is a statement that suspends the critique of the right, poisoning the well of the left to place confirmation bias of the viewer/reader that the left can't and the right can.
I've seen many memes on the right that I don't consider funny or thought provoking.
It is really just all subjective to the viewer and the values they hold.