He is playing to his base and is just as guilty as they are.  trump carried the birther issue up to the time he was elected and never apologized for it, he simply stated that Mr. Obama was born in the USA, period.  You cannot legislate these racist views but from the example set by our leader and the tone they set, keeps the racists in check.  You can legislate behavior by make rules/laws restricting certain bad behavior.  trump's behavior has given these racist the green light.