"In the Year 2000"

This sign is found in Oregon (*Picture acquired via Orcinus, via Lori Cain of the Statesmen Journal).

I'm all for freedom of expression, but where does one draw the line? Should one draw the "line" with "white supremacist Nazi's shouldn't be allowed to advertise"? The answer seems fairly obvious, though like most issues of this caliber, it is much more complicated than one would think.