Phil Fish Scenario:
Tweet: You suck
Phil Fish: No, I'm great, look at my award
Tweet: Make your game on platform X
Phil Fish: Platform X isn't even for games
One year later: I can't take it anymore, I quit videogames!
Kamiya Scenario:
Tweet: You suck
Kamiya: No, you suck
Tweet: Make your game on platform X
Kamiya: Company X paid for it / ask company X, stop asking me about it
One year later: cute babes check out my arcade PCBs, idiots check out the log
Kamiya deals with the dumbest fucking people (console warriors, racists, videogame news drama addicts) everyday because of his twitter addiction and despite yelling at them (and others lol) for not following his house rules or being confrontational idiots, it just slides off his back. Kamiya treats his twitter account like his own personal internet home, he'll get pissed if you clutter it up or fail to show some manners, but no matter how you manage to piss him off, you've already been forgotten by the next morning. In the replies at the center of his controversies, Phil Fish comes off as egotistical and insecure (I'm going to use this award to prove I'm not bad, I'm going to go the extra mile in justifying the console I chose and insult the one you want, I'm going to jump on this message board to gloat), who was so concerned and resentful towards the internet that he had a meltdown and quit the industry despite claiming at one point something along the lines that I couldn't do anything else (he got taken down by Marcus Beer of all people). Phil Fish achieved his great infamy by insulting Japanese games in a situation/manner of such douche-ness that it remains unique in the industry, but for Kamiya, if he wanted to voice he didn't like western games he'd probably say something like "no interest" in an unremarkable tweet. The dude won't even accept people bad mouthing Capcom on his behalf.
They both dish out insults and they are both under the microscope of social media, but their characters couldn't be farther apart. Kamiya is childish in the best ways, Fish is childish in the worst ways.