Most people don't expect immense hatred when they do something that others disagree with. So much conflict in human history has resulted from underestimating the vitriol of a group. You never realize how bad people can be until they show you.



The people at r/Zootopia who hated on your comic may have a right to do so, but they had NO RIGHT to treat you like shit because of it; especially when you have made good things for the fandom. The ugly opinions always are more visible because they speak louder than the good ones. You make ONE thing in a fandom that angers the majority viewpoint (Judy and Nick being lovey-dovey in this case) and you will get flak for it; its inevitable. What they consider a "mistake" and continue to hold over your head and never give you forgiveness for is to me an experiment. You tested the waters and the sharks came straight for your ass.



Despite this cruelty, I assure you any sensible person would be civil regarding the issue and merely request you don't repeat it. This story is as you said an AU (a what-if) and as a result has ZERO bearing on the "main" plot of shipping them like crazy with all the fluff in the world. It doesn't detract from your liking of what you perceive to be correct and shouldn't cloud your judgement to the point you unjustly hate on someone because it hurt your feels.



Tl:dr While it wasn't your intention to poke the bear out of malice, human beings can be very stupid and let rampant emotions get the better of them. This however is not an excuse for outright malice in return. Focus on the good in sensible people and not the idiocy of irrational ones. It will make your life much easier.