Just as to us actions & posters of Westboro Baptist Church members are unacceptable
http://www.usatoday.com/story/news/nation-now/2014/03/21/westboro-baptist-church-pickets-funerals/6688951/. They violate all the norms of decency in a civilized society, by citing their (misunderstood) right to free speech.
One has to realize that the jury is still out on whether sexual preferences is a result of nature or of nurture or both. Each side points to studies to prove their point. While the discussion is necessary on academic levels, public spaces must be sexual preference neutral.
We thought the left wing wanted to raise the bar on the quality of our political discourse.