Why am I getting counter matched in urf?

We get 5 melee top laners with no mobility. Enemy gets 5 hyper mobile adcs...

We get 5 mages with no only poke Enemy gets 5 tanks with hard engage.

We get 5 adcs They get 5 assassins

Don't flame me for "it's urf shut the fuck up the game isnt fair blah blah kill yourself" I know thats what this community is but it's so goddamn frustrating when you que for some silly fun and just get greeted by people treating this like fucking challenger ranked games.