Liberty is a funny word, it seems as almost no one truly values is or understands it. Clearly it does not mean the gays can be refused the right to marry, but equally it does not mean the those who disagree with a life style have to accept it.
So when faced with either of these situations, how do we as a society resolve them? usually with force. We demand that government step in and force the other to bow to our needs/wants/wishes. 
An attack on liberty is having the government refuse to "permit" marriage, equally it is having the government force you to bake a cake.