It does when allegations of dog whistling are levied against mainstream viewpoints. Saying "build the wall" is a white supremacist dog whistle is absolutely a means of expanding white supremacy to encompass support border enforcement. Nothing about building a wall on a national border is white supremacist. White supremacists may be in favor of such a viewpoint, but that does not make the viewpoint itself white supremacist.

Accusations of dog whistling is a very cheap and effective way of stuffing words into one's opponents' mouths and many do use it to try and paint acceptable views as white supremacist.