Just a Suggestion and Question

Why do people have the ability to ban the champion you have selected? I'm not notably mad, but why is this even an option. I just got into a game where I wanted to play my main character, then had my champion banned because a thresh support thought it was unviable or I was not skilled enough to play said champion. I don't believe the devs will see this, but I'm kind of surprised that this wasn't seen in the past years since the new champion select