So yes, in order for mankind to survive, mutants must all die.
Most mutants have powers that range from useless to blow up a city-tier.
A tiny handful have global catastrophe powers.
There are non-mutant superbeings, but they tend to get their powers as adults, and the those that are on par with the top-tier of mutants usually have something preventing them from blowing up the planet, or take great care not to.
Tomorrow a mutant could be born with the power to blow up the sun - what's to stop him from doing that, when he reaches the angsty teen years?
Earth has superhumans that can defend it from galactus etc - it does not need mutants for any reason.
All superhumans are powerful and dangerous, but only mutants are completely chaotic and uncontrollable.
Wiping out mutants isn't racism, it's survival.