Jesus and the disciples also went many places to share the news of salvation. There were some times when the people came to him but if you want to catch fish you gotta go where the fish are.
They sang songs and held signs with scriture in them. Gays are intimidated by the gospel, but the point is they were not confrontational, and could easily have been ignored. They had a perfect right to "peaceful protest" that in itself is not a crime.
No, the Christians had a portable bull horn, and used it to sing. I had no problem hearing what was beind sung by one man... in a crowd ... with background noise... from a fairly good distance.
Again, if this had been a group of mild mannered Nazi's; doing exactly the same thing (peacefully spreading their message), behaving in the same manner, the chances are very good that they would be given a choice of depart, or be arrested. The only difference is the subject matter at hand.
I don't think the police had much choice in the matter. The Gay's had paid for their assembly, merchants had set up stands to sell to the Gay crowd; and the Christians decided to descend upon the group. The Christians were not welcome, and were disruptive to the planned event.
Remove the term 'Christian' and insert another term (Insurance agents, Fireman's Ball staffers, Secretaries for the United Way), and they decided to disrupt an event; chances are they would also be given a choice between leaving, or being arrested.