Anyone using plurals for singular has no appreciation for language or culture and is at risk of loosing the benefits of both. Pronouns aren't about personal expression or feelings. They're shorthand for navigating the world -- passed on by our ancestors, tried and true. We don't pick our sex, gender, or pronouns. We dovetail as elegantly as possible into systems of meaning that have been developed over millennia and only change them if we have sorted out something demonstrably better for the vast majority of people.
I can't be a 'she' or a 'they' any more than the table I'm sitting at can be a 'car'. Those words mean different things and if we use all of these words interchangeably then they all cease to have meaning.
Take my table, for instance: It has legs and a top and it is used for resting things on. Those factors make it a table regardless of what makes me comfortable or what I wish it to be. I can call it a car, but it doesn't have wheels or doors and it doesn't drive and has never driven. I could strap some wheels on it and glue a steering wheel on the top -- might fool some myopic types, but still it wouldn't be a car and calling it one would be about as looney as calling a random guy named Steve 'they' -- which is precisely what you see when looking up mentally ill people on Wikipedia these days. And if Wikipedia doesn't understand the importance of a functional language than we're really in trouble...
Folks shouldn't mess with things they don't understand. It isn't cute. It isn't smart.
