I'm going to refuse to leave a competitive Overwatch match
Why would you refuse to leave?
I believe I was the victim of spawn camping so I feel the need to get them back.
It's frustrating sometimes to lose and not recover from a game, so I feel for you about your Overwatch game that your opponents are taking advantage of. But you are being persistent, and I applaud that. If you really do not want to give up, then you should not have to and it is very noble to finish what you start.
I'm playing with randoms and it's not fair to me that they keep doing that to me.
Since you don't know these people, there's a high likelihood that they're just trolls who get excited when you get frustrated. I understand trying to get revenge but it can be more stressful to do that than to just move on.