Behavior you just described is one of the chief problems in the structure that is "not welcoming to new players".
The fact that players feel like it is appropriate or justified in being "very hostile" to other people at any point is truly asinine. Treating another person differently based on their skill level, or style or play is unacceptable. Consistently making bad decisions? Next time imagine if you were actually in a room with this person playing a board game perhaps, or a game of soccer/football. Even if they were making poor decisions based on their skill, or just less interested in the game at hand it wouldn't give you the right to be rude or have a "fallout". Find another lobby, make sure you are playing strictly with friends, or ask the player to join a more casual lobby.
God forbid every new player doesn't buy the game with a $300 mouse and gaming computer looking to memorize the metas, reach tournament level and become a professional GOIO player. Instead of lamenting every casual player that enters the game why don't we take some responsibility for the way *we treat newer players as well* regardless of what their goals are in game.
I must say, you are very creative and very liberal with words. So I'm going to ask you: please don't put words in my mouth. I'm enough of an asshole without your help.
Furthermore, I never said flaming, raging, etc is a good thing. But I am saying that stuff like this happens. And that for the players that truly care, this abuse is targeted at malfunctioning players. If after 5 minutes of idiocies, my gunner tells me that the person causing trouble is sitting in his gun, I will shout that guy off. In turn, even I get shouted at for stuff I shouldn't have done; and instead of moping about that on the forums, I realize some other factors can be active here and that the player giving me the lecture has good intentions. That is me, I've been on both sides and I know what the captain is dealing with and I know what crewmembers are dealing with. I don't start off yelling at people and if players here claim they don't notice that, it's because they refuse to listen to anyone that isn't shouting.
Now your board game analogy. It's obvious you've never been even remotely competitive playing board games, card games, sport games that rely on teamplay. Otherwise you would know that if you were to dick around, you aren't welcome for long. The situations in these type of games still can go to a phase where people start yelling at eachother for numerous of reasons. Yet, it's less frequent because such games are usually among friends rather than strangers that wish to fuck around and annoy eachother.
Lets continue with your 300 dollar mouse remark. And I keep saying this and I know I speak for pretty much everyone: I do not care about your hardware, I don't care about the operating system you're playing this game on. Your headset can be pink, lila, magenta, or everything at the same time. I do not care. What I do care about is that you respect your captain, listen to him and communicate with your crew. Essentially, I ask of you and everyone playing this game to uphold a certain kind of standards that any respectable person should have. I'm not asking you to be good, I'm asking you to try and I want people to be willing to learn.