"We want to be able to show the members of our community that there are people just like you,”

Then why don't you come to Pride just like the rest of us? In regular clothes. I can't think of any other group of people who come to Pride in work uniforms. You've been invited to participate with t-shirts and signs identifying yourselves as police officers. What's with the uniform fetish?

Your demand to participate in uniform reads as a willful refusal to understand that your department has serious ongoing problems with LGBTQ people. If you want to be accepted as people just like everyone else, then you need to start demonstrating some humility.