Troll pick

Hi all! What is the reason behind players starting to flame right at lobby, just because i choose a champion that they consider troll pick? (Azir mid) Seriously, all of them called troll on me, i was doomed a from the start of the game, not a single gank eventough i roamed and helped with drakes. Teammates literally acting like kids._ **Anything**_ happened it was my fault: "_told you troll pick_" Should I even report them? What would you do?
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