I personally feel like you get whatever skill level you get when you get a party through DF and if you want everyone up to snuff then you should put up a PF with your standards made clear. That is certainly debatable when it comes to Coil, which is supposed to be the toughest of the endgame content. I think it's ok to leave after a couple of tries if it's clear to you that the party is doomed, but it's never okay to verbally abuse someone ever under any circumstances. It's not suddenly ok because you're playing a video game and someone is bad at it. I see that and I'm like holy hell dude do you talk that way to everyone who mildly inconveniences you?