Is there any logical reason to ban your first pick's preferred pick on blue side??

For example, if your first pick is on Jhin, and you're queued for ranked, and he has played him a total of 0 times. :^)

Is the champion a shitty one?

Ye-

{quoted}

Other than of course just being a dick?

No.

Actually, they might assume you are garbage on that champion, like someone who prefers Lee Sin but is in Silver with you, you know that they're just going to tower dive like an idiot all game long.