Denying someone access to a public place/facility to engage in a lawful activity, because you don't like the way they look or what they might say or believe really isn't kosher. Even neo-Nazis have the right to assemble and the right to use public facilities.
Now, a private club is a different matter, of course, but threatening someone with a firearm -- when that person has not harmed you or threatened you in any way (other than offending your sensibilities) is generally legally considered assault, I believe (even at a private club).
If some punk kid comes to your club range with a "Zyklon B" t-shirt on and a shaved head, you can't draw a gun on him. He may HATE Norwegians or Chilleans or whomever with all his heart, but that doesn't give you legal justification to threaten him with a weapon.
And, if he's at a public range, he has just as much right to be there as do you.
Now, he may not be ACCEPTED and WELCOMED into your group, and I don't think that would be seen as unreasonably "insular" by most people.
Still, the shooting world is EXPLODING. There are SO many more people out buying guns, joining gun clubs, competing, training, etc, these days that a lot of folks are going to have to get real comfortable with "riff raff" enjoying the facilities with them. And the sooner those "riff raff" become "friends" and shooting buddies, the better.