I don’t believe the cops who want to march are the same cops exhibiting homophobia and disdain for gay hate deaths.

Sure, but if they’re in uniform they’re representing that institution as a whole. Marching in uniform, in formation, with guns, no less.

“It’s a bit hypocritical to ban them from marching if you’re going to rely on them, as everybody does for major events, for security.”

I think that’s legally mandated. If there were any other option available I’m sure Pride In Protest would be pushing for that too.