Honestly, I agree to a point. If I'm playing ranked and I get mid (my worst lane) then 9/10 times I will lose lane and the game and screw my team over. It's not fair to the team, it's not fair to me, and it's just not fun.
But, in normals then yes, I do my best and try to learn that one lane I'm horrible at. I got a lot better than I used to be. I won as Azir vs his hard counter, I dominated as Karma (20+ kills less than 4 deaths), and I'm working on getting there.
Point is, it's ok in some games not others. I can understand people not wanting a certain lane and I'm willing to switch with them if they tell me why they don't want it. As a supp main I'll often take supp if someone asks to switch, but if they're an ass and say supp sucks I won't switch. But if they're like "I'm horrible at it" I'll happily switch and go on to dominate lol