As Ginsanchou said, any sort of kick feature in the Champ Select lobby would only really lead to abuse by players who want others to play exclusively to their standards. And besides the fact that two players is much, much too few for such a decision, there's another thing that factors into it, which is that over the past few years, Riot has been doing a lot of work to make queue times shorter, and the actual game more accessible.
When they changed over from TeamBuilder to the current Normal Queue for Draft Pick (I think it was originally called "Flex Queue"), they did so to decrease the waits people were suffering to get into a match. With TeamBuilder, players had to wait excessively long amounts of time to get the people they wanted in the roles they wanted for the teams they wanted. And if you weren't waiting for people who fit your criteria, you were waiting for people who decided to pick you for the slot in their team.
And that was genuinely fucking painful, I can speak from experience.
Adding Flex Queue (and, by extension, AutoFill) shortened the queue times dramatically. You choose two roles you want, and while AutoFill is active, you have a chance of being put into a role that's scarce on players at the time. (though that mostly just equated to Support). So, not only could you decide where you went and be put into a match regardless, but you also had the chance of shortening the queue times for everyone by going Fill or getting AutoFilled.
Then, of course, they made several changes and shaved a lot of time on the Champ Select Process, making each stage take...What, thirty seconds at most? And encouraged players to lock in their pick intent quicker (or at least, at all) by force-kicking players who didn't lock in when the timer reached zero.
Then there was the change to the ban system, where instead of going back and forth in a six-part ban stage (which could take up to three minutes if everyone was lazy), it's now everyone bans at once in the same thirty-second stage. More time shaved off in the interest of shorter queues.
And all of these changes (alongside the Low Priority Queue) work to facilitate one thing that Riot holds above pretty much any other change to queues:
Getting into the game faster.
And the concept of a kick feature in Champ Select goes so far against that goal that I doubt Riot would even think about implementing it, even ignoring the mass amount of abuse cases that would arise from it.
