glumshoe:

When people are described as “gay icons” it doesn’t necessarily mean that they are themselves gay people who are iconic—it means that something about their cultural role has been widely embraced by a significant part of a gay population, and their own sexuality or gender is irrelevant.

Judy Garland is probably the most classic example. She was such a famous gay icon, despite being a straight woman, that “friend of Dorothy” has been ingroup code for gay since the 1950’s. The same can be said for James Dean and lesbians. So when people refer to, say, Hozier as a “lesbian icon”, they’re not calling Hozier a lesbian, they’re just acknowledging that he is widely recognized as a pop culture symbol amongst many younger lesbians. There are of course many LGBTQ icons people who are themselves LGBTQ!