You cannot take away a right to enter the US from somebody who does not have it in the first place. Only citizens and permanent residents have such a right. Even people given a visa do not have this right, they still can be turned away at the border without any of their rights infringed.

This is no different, for example, from applying for a research grant and getting denied on the basis of the application. The government examined your speech in the application and decided not to give you money, is this a free speech suppression?