One reason this form of harassment is given less attention, especially in relation to harassment stemming from homophobia, is the same reason that women's stories of street harassment are often brushed off: We're supposed to be flattered by it.
When a heterosexual woman is accompanied by her partner, her chances of being harassed go down. For LGBTQ individuals the opposite happens. I've been harassed for holding hands with a boy. It's not news to anyone that it happens, but it does happen with alarming frequency.