SerotoneDeathyoh yeah i wanna play against 2 demos or 3 scouts sounds fun
No, he's saying the class limits make it inconvenient to change classes when in the rules class limits only apply in play / outside spawn. Again, give people the benefit of the doubt for the sake of a better/easier/funner experience playing the game.
Except the lack of class limits makes it easier for those rules to be broken. I don't know about in the EU cups, but in the NA cups there are multiple times where the skill level of teams that signed up are decently far apart, and without class limits there's nothing stopping a lower level team who is getting rolled by a higher level team to recognize they cant win, and use the last few rounds to troll by all going demoman or something dumb. Even if you play against that and get a default win for them breaking the rules, it still won't be enjoyable to play against.
If you want a better/easier/funner experience, taking measures to prevent any form of trolling like that would probably take priority over the 2 second frustration of not forward spawning because you clicked the wrong class in my opinion.