You mean just like it does to get a decent high mythic + group together?
I had my entire friends list filled up with tanks, healers and dps that I enjoyed playing with and when I was looking for groups I whispered them or they whispered me. That's also how I ended up in my first proper guild back in Vanilla. People that behaved badly, ninja looted, ninja pulled and such didn't get groups or guilds to play with. Even if you go on some of the big private servers today you'll end up meeting people that has good behavior and are helpful, because that's how you build a community around you.
Was there toxic people in Vanilla? Yeah but you could very easily avoid them.