LGBT: No landscaping for gays?

A company in Houston, TX sent an e-mail to a would-be-customer informing them that they could not landscape this couple's yard because the company refuses to work with homosexuals. I guess it's their right, but seriously? What does cutting grass and planting bushes have to do with who shares a bed? Some people are just so ignorant it's almost funny (if it wern't so scary!).