Hmm...I'm on the fence. While it makes me glad that gay folks are now accepted in society and no longer have to hide in the shadows; as a taxpayer it bugs me a little bit that there are government grants available for these parades. To be clear, I'm proud they can be proud but I'd rather shoot that extra tax capital to poverty or infrastructure. We're all in this together.
I'm no expert on....anything....but I believe these parades (specifically talking about PRIDE) give a lot more back to society than they get from it through government grants.
Being able to be proud of who you are means you are more able to contribute to society in a useful way. Working and paying taxes as well as making purchases and paying rent. The parade is a place to meet other people who have gone through what you have...get help if needed, or some BTDT advice.
I don't know about other cities, but Toronto gains a lot of money from the parade. People come from all over the world to attend. Lots of weddings take place, hotels, restaurants, theatre district, all have booming business during PRIDE month.