So if you join a ranked game and you go 0-3 in lane and you are trying your hardest that is trolling?
Just because you are in bronze II doesn't mean you belong there whether negative or positive. For example just because you are in bronze II you could actually deserve to be bronze V or even SIlver I either way if this is the case you will either lose or win continuously until you reach an elo where you win 50% of your matches this is what an elo system creates. If this is the case even for the people that try their best they will feed if they are not good enough this doesn't mean they are trolling.
Check your logic. Also sometimes people have bad games or the enemy laner is just better then them. For example because I checked your match history you have done well in a few past ranked games. Does this mean the person you stomped in lane is trolling not necessarily just that you are better then them. Hope that makes sense.
Also from Bronze II all the way to Diamond V (I've been in bronze silver plat and now diamond speaking from experience) you will see unintentionally feeding so brace yourself it is much different and not even close to trolling.