The NY Times has a more in-depth look at the issue today:
https://www.nytimes.com/2021/05/15/nyregion/nyc-pride-nypd-banned.html?action=click&module=In%20Other%20News&pgtype=Homepage
As for the relevance of the parade, think of young gays newly out and the thrill they get from flaunting their orientation to the world on Gay Pride Day. Their confidence in who they are is reinforced by the crowds. Us old fogies typically don't need that reinforcement, but I remember when I also shared that thrill. Parades now rather bore me, but it wasn't always the case.