General anime fans got one idea of the type of person Iris was in their head
>ie. "you're just a kid!" "i'm so much better than you!"
without watching the show in its entirety, (mostly because it's terrible) where Iris is actually, for better or worse, an agreeable friend to Ash and a kind, driven person.
With Goh, it feels like hate specifically from Ashfags. Any normal person who watches that show would think Goh was a fine character, maybe a little OP with the catching, but his characterization and important scenes are slightly better than the average Pokeslop. Most of the outrage surrounding him is that he gets starters, Suicune & Regieleki, and some things like Flygon, Absol, Scizor, and Frogadier, Pokemon that fanboys swear up and down were 'for Ash'.
Iris broke the fandom more because she caused a larger amount of people to exit the show at once, whereas Goh breaks people who'll never stop watching anyway.