Did the moderation algorithm seriously give somebody a warning for noting that Trump supporters are racist?
yep
and specifically for saying that LIBERAL trump voters who voted for trump are racist, because, as they accurately pointed out, trump was not the better liberal alternative over hillary on any single issue
so if you say you are liberal, but still voted for trump, there really cannot have been anything other than his racism that could have possibly appealed to you
(as opposed to if you say you are right wing on economical issues, in which case it is conceivable you voted for trump for economic policy that would benefit you rather than for his racism)
(i guess a possible alternative to being a racist if you are a liberal who voted for trump would be to be really fucking dumb and/or uninformed)
so it was a ridiculous moderation action, and i can only assume the mod misunderstood the post
(i have also seen off-site that alt-right people/trolls say they like to spam the report button on innocent posts in order to make the moderators exhausted enough by all the reports that they slap a token warning on there to shut those reports up, so i guess that may have been another possible explanation for what went on with that particular moderating decision)