The only difference between a text based post & meme is a visual aid.
The visual aid doesn't "breed tribalism".
Tribes form around ideas, not visual aids.
Discussion
I don't think that's the only difference. I think you should look into the research on symbology and it's relationship to propaganda, demagoguery and in-group behaviors.
Classic case of correlation vs causation confusion.
Idea - tribe - propaganda
In that order.
Just like the egg comes before the chicken.