Because aging politicians do not adequately represent the majority of their constituents.
Humans memorize the information relative to them. If politicians memorize racism they’ll make racist policy.
I don’t want people who think in 100 year old social terms alone deciding my fate.
Society that never retires old ideas, demands speech stay on specific rails is hardly free. That type of governance is the basis of a police state.
Discriminating against someone on the basis of age is anti-social behavior.