So, where's the magic threshold for when something should be addressed?

My school in rural Kansas (town of 2800) had an LGBT student that graduated last year.  Very bright...4.0 student.  Only known gay student in the building.  Occasionally subjected to slurs.  

Tell me.....should the school just simply have ignored it, since it "isn't even widespread".

What about the biracial kid that had "Stupid N_____" written on his car.  He's only one of a few non-white kids in the building.  Again....should we have just ignored the issue, since it "isn't widespread"?