I got yelled at in M+ because I don't know what "soak at the back" means

Great, so form a group of like minded people. Form a guild. Talk among each other, decide how you want to play and go for it.

But if you decide to jump into a random PUG (Pick Up Game) then play with who you get. Don’t be the person who makes life miserable for people around you just because you won’t take the effort to form a guild.