More importantly, Pride itself a reference to the Stonewall Riots, in which cops brutally assaulted LGBTQ+ citizens with great malice and the citizens fought back.

June 28th, 1969

https://en.wikipedia.org/wiki/Stonewall_riots

The first Pride Parade was a year later, on June 27th, 1970

https://en.wikipedia.org/wiki/Pride_parade#First_pride_marches

The reason cops shouldn't be allowed at Pride is because cops violence against the LGBTQ+ community is why Pride fucking exists to begin with.