I know this is not the case, but if it came out that TM had a history with hanging out with gang members, you don't think that would be relevant in any way?
Not relevant in ANY way. Here's why. Trayvon, a complete unknown to GZ, was walking down the street. How would GZ have ANY way to know at that point that Trayvon hung with gang members, was on parole for murder, was awaiting trial for burglary, was a meth addict, etc (none of which is true, this is all hypothetical).
Trayvon was walking down the street. How does that merit ANY contact from GZ whatsoever?
We know from GZ's own voice that he was spoiling for a fight. Even on the phone with 911, he couldn't give ANY valid reasons for stalking him.
I'm guessing Trayvon may have faced his stalker in an effort to get him to back off. It is what I would do myself so as to show that I was not intimidated, then I would head home as quickly as possible by the shortest and safest route.
I think GZ was infuriated at Trayvon's seeming lack of fear of him, which we know from the gf's conversation was just bravado to show he wasn't intimidated. I think GZ felt disrespected by this and his well known temper and need to control ran away with him.
It's so very sad. But, no, NOTHING Trayvon might have done or been involved in had ANYTHING to do with the choices GZ made that night. Anything he might have ASSUMED about Trayvon would have ALL been bias at that point, plain and simple.