Soooo, lemme guess, you're one of those people who think trans and intersex women can't be lesbians?
Nezchan explained this perfectly well, futa has nothing to do with being trans. It's a cis girl sprouting a penis for sexual purposes only.
Let me explain something to you. I am intersex, I am a woman with a penis, as well as a partial uterus, and vaginal opening.
It's nice to know my existence is just a fetish then.
(also, we don't know the context of this particular Eli, so for all we know, she could be intersex like myself, or trans)
But it bothers me when the "futa is cancer infecting yuri" because for me, it's one of the few times where I can personally relate to the character.