I just got out of a champion select where this happened
: I'm still practicing ADC, so bear with me
Support: yeah... practice in bots. I'm a great support and now its wasted
Support: gonna need somebody to carry you. Locks 
"support."
I really don't get the nerve of some players. uhhh
Well, that's annoying but just hold off on the apologetics until everyone has picked. That completely avoids such trolls.
People need to realize that only so much can be learned from playing bots. You won't improve after a certain point if you just play against the computer.
I am going to be honest, I am a support and if my adc turns out to be 'learning' I will build a little more carry to be able to compensate mistakes but it's not that I am trying to become carry or ruin his whole game like that person does.
Sadly my helping seems not to be appreciated and they get angry for no reason. So I understand your problem but a learning adc can also be nice to the support who is going to help him instead of immediately being toxic at him for doing a bit more damage than usual.
In these cases I even wonder if it's a learning adc or that he wants an excuse for playing not as good or a reason to be toxic at someone in the team for helping (and in his eyes ruining) him and his learning experience
As if being a great support means shit in bots. A great support would actually support the guy. Point out things that could be done bettet, nicely, and above all support the learning individual.
