My old high school crush has a ๐ณ๏ธโ๐ in her Instagram bio. But sheโs getting married to a man. Why did she put that flag in her Instagram bio for if sheโs getting married to a man?
Showing support for the LGBTQ+ cummunity. Being straight AKA cis-gendered doesn't in any way put one in opposition to the non-cis- community. In fact I think it's a little weird to presume that the cis- wouldn't support the non-cis-.
One minor point. Straight is about who you are attracted to, cis is about your gender identity. Most people are straight and cis, but you can be cis + gay, or straight + trans, or any combination. ๐
She probably wants people to know she is bisexual. Marrying a man doesn't make someone stop being bisexual. Bisexual people are constantly being erased. She is no less a part of the LGBTQ+ community for marrying a man.