Who's fault would this be?

What is you guys opinions considering a case like this? --- The game is only a few minutes in, during the lane phase. ADC and support at bot lane. One of them makes a mistake. (It can be either) And gives double kill/first blood. Or support took a minion by mistake. ADC start to rage. ADC flames support. Such as 'You suck', 'You make us lose game', 'You troll', 'You tilt me/you make me play bad', 'I'm playing 1v2' Support doesn't say anything at all. They go back to lane. ADC is angry, and makes another mistake. ADC dies. He will keep flame and blame the support for everything. ADC would keep saying 'You've ruined my lane'. This goes on for longer... Support gets annoyed and don't want to take more crap from the ADC. Because no matter what they do, ADC will trash talk them for all his future mistakes. Support guy doesn't WANT to stay together with this ADC anymore. Also, bot is lost, if support stay, they might die again. So support tells the ADC: 'I'm not staying bot with you anymore' and start roaming. In cases support does good roam and manages to get team kills from other lanes. The rest of the team would be 'neutral' and not say a thing while ADC start type in all chat 'My support is trolling me' 'They are leaving me 1v2' 'Report'. Enemy team will say 'We will report your support for trolling.' In case support didn't manage to roam well. Basically 'not being very useful'... The WHOLE team would tell the support 'Stop trolling' 'Go back bot' 'If you don't go back bot we all will report you.' If support decide to go back bot and bot keeps dying, the rest of the team would go: 'report bot' ADC will keep flaming support no matter. --- Happened to me a few times when I played support. And some cases it was clearly the ADC's fault entirely. Sure I can mute. But I just couldn't bring myself to stick and help a guy who flames me like that. If I did, I feel like I'm letting myself getting pushed around by the ADC however they want. If they die, it is MY FAULT, if we get a kill it is THEIR SKILL. Really... My options would either go afk, which I don't want... or help out my other lanes. But (If I didn't make a successful roam) it would put the rest of my team against me as well. I feel it is very unfair.
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