This sounds eerily similar to the Zen one trick in my Eichenwalde game the other day. My team and I were initially on the fence about this player on Zen. However, after some struggling, we politely requested for a Mercy for a Pharmercy comp. Not because this Zen was bad, but because the enemy Doomfist/Reaper was an unstoppable force in picking off the Zen and subsequently the rest of our team despite my efforts in trying to keep the backline alive. Of course, this Zen was not verbally communicating in voice chat, did not switch, and it doesn't help that this player was unranked with a private profile.

I totally get wanting to play a fun hero. Having felt my fair share of the burden as a low masters Genji main, it just makes more sense to play other characters given the current state of the game. Here's the kicker though; if you want to play a fun hero, go for it. But you have to demonstrate what value you're providing to the team through being positive, making call-outs (discords, ult tracking, etc) and potentially picks. If you and your team are not getting value and losing fights, you have to switch. Unfortunately there are other supports with just better (if not broken) utility, and that's the main reason people are so adamant about having you switch. It significantly increase the chances of the team's success.

Trust me, I totally get not wanting to play these other cheesy heroes. It's the same exact reason I always insta-lock Genji first, but switch to someone else if we're losing...except Doomfist. I prefer the adrenaline rush of being a lethal, currently useless assassin and dislike the not-so-fun cheesy Doomfist. My point is that you'll have to come to a compromise with yourself and your team. Or, wait another 6 months for new balances and hope Zen is more viable.

I personally play competitive with winning as a priority. It's not fair to the rest of your team taking time out of their day to rank up (assuming they're trying to play as a team). So, as someone else here mentioned, it's not a form of throwing initially. But until shit starts hitting the fan, you are inherently soft-throwing, regardless of how good you are.