Government Should Be Viewpoint Neutral

The rainbow flag is recognized the world over as the primary symbol of "Gay Pride". It is, AFAIK, the ONLY symbol used to represent and convey the queer viewpoint. But you seem to be asserting that painting what must be the world's largest rendition of this symbol across a major street, and then making it the basis for a tourist advertising campaign sophisticated and well funded enough to attract international tourists, is viewpoint neutral. You seem to be denying the obvious fact that this is brilliantly (pun intended) conceived and executed civic speech to promoting the queer viewpoint.

Your assertion that painting a giant rainbow flag has nothing to do with promoting the queer viewpoint seems like equivalent to an assertion that painting a giant swastika on the pavement of an intersection in a neighborhood populated by Aryan Race White Supremicists would have nothing to do with promoting racism.

How would you feel if your tax money was used to paint a giant swastika on the road and to use that as the basis for a major advertising campaign?

This is definitely speech. It is definitely not viewpoint neutral. And it is definitely funded by government, over the objections of the minority of voterss who oppose the viewpoint.