Trans-inclusive definitions of gay, bi, and lesbian don't exist to slight other sexuality labels. They were created by trans people for the purpose of supporting trans people. And yes, we have a long history of checking gay, lesbian, and bi people on trans-exclusive definitions.
I don’t know what sparked this message, but the only time I talk about trans inclusive definitions is when people define pan that way to say other identities aren’t. but yeah, I mean, I’ve read stories about how when pan first came about, people felt like someone saying they were pan was like saying they were trans or non-binary friendly. so I totally get how trans inclusive definitions can be beneficial, and why trans people really should be the ones controlling the discussion about this.
The number of times lately I've seen people try to exclude trans and non-binary people from the "lesbian" label in particular has dismayed me. Trans women are women. Non-binary people can define themselves as women (demigirls and gender-fluid folk are two examples).
Excluding trans people makes you look like ignorant bigots, and plays right into the hands of the conservatives who want LGBT people stripped of their rights. After the trans people come the bi folks, and guess what, lesbians - you're next.