For instance, you don't have to allow pro-Obama rallies on your front yard.
All your front yard merry-makers have a first amendment right to clamor for any kind of leadership they favor - but not on your front yard. That would be at your discretion.
If the police wanted to stop the demonstration, they could only do so under specific circumstances. Parade permits are lawful things, disturbing the peace is a legit charge, that sort of stuff.
The police can't ask me to stop wearing Obama Sucks tee shirts, but a business requiring a shirt and tie could tell me I couldn't
My gun isn't universally welcome at businesses, as my dollars aren't universally welcome, either.
My favorite civil rights bar bet is whether or not there is an American right to free speech. There's not - there's an American guarantee of your rights of free speech, and a pledge that Congress shall make no icky laws, but the right isn't American.
Civil rights come from outside American jurisdiction, which makes them out of reach and beyond erosion. Supposedly.