C'mon, these are jokes and they are ment to make some people laugh, not to offend other people. I guess those may be cultural differences that make you take what people say more seriously than other Europeans. All the 'kapikulu' and 'teamkill' connection comes from long time ago when (probably) high ping or lack of awarness of Turkish players caused them to teamhit quite often.
If you take a look at Harpag and Grey Order, people still keep joking about their 10000 cdkeys and all in all, jokes about Polish and Russian players happen quite often yet nobody quits because of this. It's because they all know these are jokes and stereotypes.
You should chill out and accept that internet is a place that requires some sort of thick skin and distance. Also please keep in mind the cultural differences and don't take it seriously when other people joke about Turkish players (for example call you 'kebap' or something).