Someone explain to me the rationale behind flaming your jungler for taking a kill in a gank

The only reason I would flame is if I am very kill dependant early game champion, and you are something like Karthus, and you can jsut farm into relevancy anyway

For the same reason anyone flames anyone for "kill stealing".

They suck and have a terrible attitude.

well i will flame the jungler if he flashes in to steal my solo kill when the opponent is 10hp and ignited. and no, playing doesn't give you permission to do that.