Anything can work if you actually put some effort in. The problem is that no one wants to try any comps that are even remotely unusual because "No, the meta tho."
And no, it's actually a terrible idea to ask someone to switch to a character that they're less familiar with just because it technically fits the team better. Don't ask me to switch from Mei to McCree or Roadhog and then bitch at me when it doesn't work out so well. If someone is doing well with a character, let them play it. Don't just give up at second 1 because of a pick you don't agree with.
They're usually not. And in a lot of situations when you let that slide, they get carried to victory, reinforcing their idea that whatever shitty thing they're playing works. Played with a Torbjorn on ATTACK on Hanamura earlier, and his turret never stayed up for more than 10 seconds, and he was constantly getting picked. We took A and B despite him, not because of him, and I'm sure because that was a win he feels his pick is justified, but he was barely present for any of the team engagements.
I don't think someone should switch from a sensible pick to whatever someone tells them -- I always lay out that I can play Zarya, Roadhog, D.Va, Ana, and Lucio really well, but I am a terrible Rein. Usually with a good team, we can talk through everyone's strengths/weaknesses and figure out what adjustments to make before the game starts or during. It's when there's a polite "Hey, it doesn't seem like Symmetra is working for this push, can we potentially get a DPS? Can anyone switch/swap or can symm play something else?" and you see "X has left the voice channel" and they then become a fucking disturbed toddler because someone is asking them to make an adjustment. If you can ONLY play a single class and that is ALL you play, you do not belong in competitive, plain and simple. What if someone else picks it before you, what are you going to do? Quit? Cry until they switch?
Be flexible, reasonable, and willing to work as a team. This isn't deathmatch, it's a team game, and the team dynamics are just as important as your individual performance. If you be doing really "GOOD" with a hero but it can easily not be the contribution the team needs, and you're not going to win.
There's PLENTY of room for jerking off and playing whatever trash you want in QP. At least come into Competitive with some semblance of a reasonable attitude and the ability to compromise/be a team player.
Eh, its a video game and a bought it. So i''ll play whatever mode I want, thank you. When you start buying me video games and paying my bills you can dictate where I go.
But even more so than that? How do you know I play on here, how do you know I don't play multiple heroes, how do you know that in the hypothetical situation this wasn't a situation where there was 1 role that needed to be filled and I liked a specific character in that role. You are so up your own rear end about comp ready to assume that people are selfish to just accuse me of being some " main guy " and having the wrong attitude about competitive.
Along with that, lets go back a sec, what if I don't find the suggested hero fun? Should I stop playing the game? Should I not play , because you called me selfish. You are suggesting that that I have some type of inherit character flaw, because i'm not playing a video the way you want me to play. Do you know how crazy that sounds?
What a trash entitled attitude. People like you honestly ruin the game for others. You can not be a team player and just do whatever you want in Quick Play, where you are not ruining the game for others. Your "my way or the highway" attitude is one of the most toxic and destructive things in Competitive Overwatch.