Because we are not their appraisers. We are their clients.
An interesting thing a friend once told me; there's a difference between a customer and a client.
A customer is the guy who goes to an auto repair shop and can name the parts that he suspects are broken, give reasons why, and may even know what the replacement parts will cost.
A client is the guy who goes to an auto repair shop and says, "My car doesn't work," or "My car makes [this noise]," and answers the questions the mechanic asks them without understanding the reason for the questions. Then he comes back, pays whatever, and is none the wiser for how the car was fixed.
I'm saying this as a dedicated math-/theory-crafter who spends a lot of time debating balance; well over 90% of the people in Riot's community couldn't understand balance if you showed them a see-saw with two ten-pound weights on the ends. As much as they have an opinion, it's every bit Riot's prerogative to disregard our opinions if they don't think it's worth sifting through the garbage for the one smart guy with the one good idea.