You’re right, there are canon lesbians. Ruby and sapphire. There’s also someone who is canonically bi pan or demi. Pearl.
I mean, everyone was so quick to ship her and rose after rainbow quartz but as soon as she does they same dance with greg, everyone is all “nop, they’re just friends”

It’s not just about headcanons, it’s about the double standard. Also the fact that the entire episode was about her letting go and moving on, something the Pearl rose shippers clearly missed.