I think that "cheap" and "plastic" may be the answer. We have the same problem with the kitchen sink faucets in our Flagstaff. Drives you nuts, doesn't it? At least they don't leak.
Happy Camping! ///// Richard D.
2006 4x4 Ford 250 SD / 2007 Flagstaff 827 FLS
One very patient wife and one furry child who travels with us. Forty-two years of trailering and camping, and I still have a blast.