At the pride parade in Washington, D.C., earlier this month, accounting giant Deloitte promoted its support of the LGBTQ community: In June 2023, Deloitte produced a report on "LGBT+ Inclusion @ Work." In a letter accompanying the report, Emma Codd, the company's Global Chief Diversity, Equality and Inclusion Officer, said she hoped it would enable organizations "to take the necessary steps to turn positive messaging on LGBT+ inclusion into concrete actions."
Even barring actual harm done against the queer community, there really should be a requirement that companies using pride flags for advertising contribute in some way to LGBTQ+ organizations. Otherwise all it will ever mean is: “we’ll take your money.”
I think you’re going to have to use trademarks for this.
Start a non-profit group promoting queer community rights, create a trademarkable logo (maybe a rainbow flag could be used, or you might need more unique symbology) and then you can license that logo only to companies that do actually support the cause.