To delve into a slight tangent on your final point about the grammatical quirk of writing in all-lowercase, I'm curious as to your thoughts on a related question. What of an individual who prefers their name be written with lowercase letters? To use my own handle as an example, imagine that I requested that others refer to me as "ava" rather than "Ava", and had styled my display name accordingly. Does your opinion vary depending on whether it's a chosen name as opposed to a handle?
I have someone in my circles who prefers her name be written thusly, and while I occasionally find her somewhat inappropriately (unfairly? rashly? my vocabulary fails me at present...) militant about the topic when strangers err, I have no opposition to using the name for her as she requests, whereas I comparatively share your reservations about the use of capitalized pronouns and their associations with dynamics of power/relationship between parties.
I wonder too how I might feel should a requested name require other deviations from standard grammar, such as unusual punctuation. Were I to identify myself as "Ava!" it would certainly cause some occasionally grammatical frustrations, but I wonder if a reason given might affect the perception either in favor or against adoption. For example, the Sharks! installation rather literally evokes exclamation through its name.
Let's not make unfounded and harmful claims that being LGBTQ is some sort of toxin-related defect, unless you're prepared to provide some sort of evidence to that effect. There is ample historical evidence of the existence of LGBT individuals dating back thousands of years.