Define Discrimination

Huge billboard next to the mid-Valley Parkway advertising the Gay telephone directory.

If I don't allow gays to be included in my telephone directory, that is discrimination. If I don't allow diverse ethnic groups in my telephone directory, that is racism.

However, if I publish a "straight" telephone directory, that isn't discrimination because if it's okay to have a "gay" telephone directory, then it's okay to have a straight telephone directory, right?