Can someone please explain to me how a student's artwork depicting a normal heterosexual family is considered "offensive," nowadays????

http://www.theblaze.com/stories/school- ... -marriage/
Now, I don't have any problems with homosexuals or lesbians per se--as I have friends who are gay. But why are some gay groups so adamant in pushing their agenda into everyone's faces? I'm sick and tired of them trying to enforce their values onto every heterosexual person in this country. It makes me want to puke....A student mural at Pilgrim High School in Warwick, Rhode Island, was reportedly deemed inappropriate and banned by a public high school due to its depiction of a man, woman and child holding hands. The couple, clearly engaged in a straight, monogamous relationship, are seen standing with what appears to be their child.
Was there something else more sinister presented in the painting, you ask — an offensive message or an inappropriate character attribute? According to news reports, the school painted over this portion of the mural out of fear that it would offend people who live alternative lifestyles.