“Politicians know they can’t say or do say certain things in front of voters without it hurting them at the ballot box.”
This is an expectation nurtured by the modern Legacy Media and just accepted by the onlookers.
Times have changed and standards have certainly changed. You hear the F-bomb on T.V., in the movies, etc. all the time now. Fifty years ago if he said that it might have ruined his political career. Not anymore, and Trump’s instincts must have told him that.