No, that's incorrect. The power of the mason role is that it prevents a mislynch.

They didn't kill you even though you claimed mason.

If we just let people off the hook for claiming mason, it would be a great mafia claim.

Having a couple masons killed is no big loss compared to a mislynch. There are roles that it hurts the town much more to have nightkilled, and mislynches are very bad for the town.