"And then I was forced to play X ADC"

I have no idea how this came about. I'm talking about when someone describes a game that they played where someone trolled in champ select and so that player "had" to take the champ that they selected to a different lane and build them differently than they usually would.

For instance when people say "I was forced to play Singed/Riven/Volibear ADC because someone else picked another top after me and wouldnt change their pick even though they were later in the order than I was."

First of all, whatever. I personally would like to thank you for going to a different lane instead of trolling or afking in response. But after that, why do you have to change how you want to play your champ simply because your team lacks a meta role? ADC singed for instance, is going to be absolute garbage. If this happens to you where another player trolls champ select and forces you into another lane after you had already been locked in, just go to said lane and play how you want to play your champ, such as tank on singed/Voli, AD Caster on Riven, etc. instead of trying to build your champ for something that they were never meant for.

I have never gotten how this happens or why people use it for an excuse