This is complete nonsense. Many presidents have been both threatened and attacked - including Obama - without feeling the need to illegally infringe upon people’s legal rights in public spaces.
If the President feels threatened in a public venue where concealed carry is allowed, they have the option of private one instead. And if they refuse to change plans and go ahead with the public venue, they have the option of armed security in the form of the Secret Service.
I’ve never, ever heard of people being denied concealed carry in a public place for the sake of protecting a president, even with four different presidents having died due to attacks in public venues by assassins with concealed weapons.