My guess is that it was an emotionally-driven protest of the Republican platform's stance against gay marriage, and not meant to harm or really frighten anyone. Probably someone who cannot fathom that there is a reason (other than pure hatred) not to change the definition of marriage.
Fire a shot into a building and not mean to harm or frighten anyone?
Reminds me of a radio contest to determine the biggest redneck. One question was, what's the biggest thing you've ever shot. The eventual winner said "a building". "Was anyone in it?????!" "Uh .... I dunno."