It prob is just light hearted stuff Genocider, but if it is bothering you then you can pm me or any of the other advisors about it. The individual might not even know that what they are doing is even bothering you. I talk some smack pretty often but its always light hearted and never meant to put down anyone. I usually only mess with snipers and really good players.
Well everytime I die on avalanche while playing against this certain person, he will ALWAYS laugh at me and its seriously getting on my nerves. -.-
Now that he knows it rattles you, he's gonna keep doing it. That's taunting, but I don't personally consider it a lack of respect. There have been times though, that I wished I could see names over the enemy so I could target specific individuals. That's probably why Valve didn't implement that specific feature.
My advice is cowboy up and be happy when you kill him back.