Of course he would. Anyone would. Imagine working somewhere and then the boss tells you "Nah, fuck your pay, get out of here". then have no recourses because "it's legal". This is what piracy is, people enjoying the work of someone else without paying for it. It's clear as day that people would be pissed about it.
But instead of encouraging the pirates to support him, you go around and tell people that "it's not necessary", half of the people here are screeching and bitching at him, while having paid $zero, only taking and taking and not giving back. Yet you're surprised he's pissed?
You think devs are robots or something? You think they're Jesus?
If you take something and don't pay with money, at least pay with something else. Your body, for example. You can send him encouragement, send him good words, help other players, write wikis and walkthroughs, send him typo corrections, bug reports, etc.
If after all that he still acts like a little bitch? THEN yeah, sure. Fuck him.
But right now after the shitfest I'm seeing in here? I'm on his side 100%. I'm not even interested in his goddamn game, I'm not into cucking and shota shit, but the man still deserves better treatment that what you people are giving him.