Thank you for all the honest responses!
Call me a masochist, but I try to avoid blocking anyone based on skill, purely because I fear the segregation between inexperienced and experienced might hurt the community overall. I mean, being an outsider to the core high-level friendship groups, I get to be on the receiving end of the skill concentration that creates. I even pissed and moaned about that on here too.
I think my blocks will be reserved for those truly beyond redemption, lest I contribute to something I believe hurts the player retention further than it already is by the fast breakout of novice matchmaker. I know a lot of people want this game to stay niche, as it keeps the toxicity low and the community tight knit, but, as far as the games survivability goes, I'm not so sure myself. People duck out after repeated stomps. It even demoralised me a hell of a lot. Thankfully, I took it as a challenge more than a defeat.
I've gotten better at not getting mad at losses these days, even when I'm totally outstacked or dealing with terrible allies/crew. I feel it teaches me to adapt to bad situations a little better. A meatgrind ally, for example, teaches me to focus targets based on observation rather than communication. Eh.
When I get lumped with a bad or inexperienced crew, my coping mechanism has been to become a calm teacher. I can educate at least a rudimentary set of strategies to make a competent crew/captain, although I still have a lot of learning to do myself. (Last bit comes from being forced out of my comfort zone by a higher-level captain today, who made me use the mine launcher and lumberjack; two guns I have avoided like the plague due to me not feeling able to make good use of them yet.)
When it comes to the people that won't take advice, are abrasive or are trolling, I just repeat to myself that it is not worth getting angry over. I mean, the trolls are looking for that so giving that satisfaction - even in principle - is to be dodged and those abrasive players I simply consider it a learning experience for them. Their mistakes made us lose and they'll probably have to sit and think in the naughty corner for that prior to their next game.
Thanks again, all.