Not in the MLP fandom but I always stayed away from the whole "derp" thing for this reason.

But then again I never thought of "stupid" as ableist until relatively recently, and it's pretty tough to drop it from my vocabulary.

(Not that this is about poor me and my poor vocabulary. But really anything referring to intelligence, including just "unintelligent" is ableist and it's pretty damn tough to get rid of it all no matter how much I try.)