LogFAQs > #973961941

The trans and BIPOC colors being a triangle represents the intersectionality of these groups within the gay community and their role as the foundation of modern-day pride movements (The Stonewall Riots).

The rainbow flag is more specific to Gay/Lesbian/Bisexual people. A trans person can still be straight, or gay, or bi.

AAPI is sometimes included in these flag designs, but it's a much smaller market and some critics (not me personally) say that these groups experience discrimination disconnected from queer discrimination and/or lack the same (United States) historical significance in LGBT history as black and brown people.