He's been making an ass of himself on the internet long, long before he came to OnA's attention, before twitter was even a thing. There's some material under Kempesh in this thread that shows he was the same shitty person before his first wife left him (and he threatened to kill her and his own child, who he abandoned).
As for the escalation, it was pretty gradual, but I'm pretty sure this all became locked in with "No child, you did not fart in my wife's vagina." It's like giving a kid a toy that makes an obnoxious sound, that trigger or string is going to be pulled until the battery dies. Which, just looking at Patrick, should be within the next 10-15 years, if that.