There are no circumstances where people who rally under this banner should be treated with dignity or we should find ways to accept them in the community, even if the parade weren’t about supporting and endorsing that lifestyle. If they committed their abhorrent aveiras in private without declaring to the world they commit this heinous sin no one would not treat them without dignity, as no one would be the wiser for their private sins. The fact is they insist on making their sinful ways a matter of the public record in addition to demanding respect for their abominable transgressions.
If someone merely was attracted to this sin without actually engaging in it, he wouldn’t be declaring to the world his attraction to the sin anymore than someone disposed to theft or adultery would march in a thieves or adulterers pride parade.