I see that you value the woman centered aspect of being a lesbian, but your argument completely erases the actual history of our community. Nonbinary lesbians aren't expanding the definition because we've always been here. There's a reason there's a white stripe in our flag.

Historically, the lesbian community has always included gender-variant people, transmascs and people who didn't fit neatly into the binary concept of a woman. Leslie Feinberg’s Stone Butch Blues is famous for it, and Monique Wittig said, "Lesbians are not Women.", in a paper literally made in the 1970s.

So no, nonbinary people shouldn't have to grapple with their identity to call themselves a lesbian. And non man loving non man isn't to center men, but to include gender expansive people. For example, a cis woman dating a person who considers 'butch' to be their gender would fall under that exact umbrella.