Would you consider it ksing

Today I was playing support blitz with my adc ez, enemy laners were tahm sup and vayne adc Early game (just as low elo vayne are) she tried to kill ez even being outta position only way to save him was to pull her towards me due to minions and my pull and auto she died , a lil bit later enemy jungle ganked us vayne focused on adc popped her ult to stop her from q and help low hp ez escape I have to ult and guess what she died again thanks to minions, but what happened next was wierd she said your ez sucks, he is support your blitz is adc and all that salt on ez and accused me for ksing even though ez was cool with all this Id like to know is it really ksing that I just did and is there a way I could have responded to situations so that adc get kills or is it OK for me to kill whoever is a threat to my adc so that he survive as I think a kill will be like a minion wave which he can get with enemy being dead.