Hmm. So that makes it impossible to judge someone by any other criteria than how they treat you personally. It seems to me that this particular method of judging others would make it difficult for an internet community to thrive as it would be a conglomeration of one-on-one relationships with no real community involved.
If I started gay-bashing Squiddy but didn't say anything bad to you, this would not affect your opinion of me?
I think that's a slightly different issue. I wouldn't have an issue with you for getting involved in an argument with Squiddy. I would also try not to judge you for a homophobic comment made during an argument, even though I wouldn't like it much.
I would have an issue with your homophobia, but not because it was aimed at Squiddy. Same would apply to racism, sexism, etc.
Dunno if that makes sense at all. I might not be explaining it very well.