In that case, the post clearly identifies the problem:
> Identities are fluid and unstoppable which makes mapping them to a formal unchanging universal character set incompatible.
If you really want to have identity flags encoded in spite of that, you don't really need Unicode's blessing. The pride flag is already not a single character anyway, it's U+1F3F3 U+FE0F U+200D U+1F308 (white flag -- emoji force -- ZWJ -- rainbow) and you can always create new ZWJ sequences with your own font. Or you can make a font that automatically synthesizes flags from some ZWJ sequence pattern, which is no longer semantically valid but should be much more flexible. Once they got sufficiently popular, there is no other reason that your new ZWJ sequence(s) shouldn't go into Unicode per se.
Unicode's decision to not process non-country flag emoji proposals is because they are closely tied with (minority) groups and Unicode wasn't expected to do any resulting conflict resolution. If you can somehow resolve that problem in advance, then you should probably do that first and propose what you've done.
> Identities are fluid and unstoppable which makes mapping them to a formal unchanging universal character set incompatible.
If you really want to have identity flags encoded in spite of that, you don't really need Unicode's blessing. The pride flag is already not a single character anyway, it's U+1F3F3 U+FE0F U+200D U+1F308 (white flag -- emoji force -- ZWJ -- rainbow) and you can always create new ZWJ sequences with your own font. Or you can make a font that automatically synthesizes flags from some ZWJ sequence pattern, which is no longer semantically valid but should be much more flexible. Once they got sufficiently popular, there is no other reason that your new ZWJ sequence(s) shouldn't go into Unicode per se.
Unicode's decision to not process non-country flag emoji proposals is because they are closely tied with (minority) groups and Unicode wasn't expected to do any resulting conflict resolution. If you can somehow resolve that problem in advance, then you should probably do that first and propose what you've done.