Well yes, but it seems like it’d be worth giving that a shot before we start workarounding it by implementing bots. 
I imagine we’d go to GitHub with something like “we’d like to be able to disable the -1 reaction on our repos” [and possibly the ‘confused’ one too, which comes off as more of a “meh” in practice], and then maybe they’d come back to us with something like “ok, each org/repo now gets to choose which 6 emoji are available as reactions”. (Which sounds like a reasonable approach to me - but maybe they also have other priorities like wanting the set of reactions to be consistent across their website.)
(If something like that does happen, then I’d also really want to have distinct reactions for “good comment” and/or “thanks”, versus “yes, I agree”!)