No, there's no water industry conspiracy to try to force you to buy water on airplanes. I travel all over and am yet to have an airplane ever complain or take away the water I pretty much always bring on board even though I'm flying up front.
The airlines also don't set TSA policy though obviously they have people's ear.
The whole Clear thing was a mess and it largely used to screw over elite flyers. Places like MCO have no elite lineup but they have Clear.