Trans-folk exist. Get over it.
If you're a radical feminist, transsexual women and transgender people exist. Get over it. They're not going to disappear because you don't like them. You can't legislate them out of existence, à la Saudi Arabia and other oh-so-enlightened "civilized" societies. The question of whether they violate what it means to be a woman has been answered by the simple fact that they exist. Deal with it.
If you're a radical trans-feminist or a transsexual separatist: transgendered folk exist. Get over it. They won't go away because you don't like them. You can't legislate them out of existence à la Saudi Arabia and other oh-so-enlightened "civilized" societies. The question of whether they deserve rights is answered by the simple fact that they exist. Deal with it.
Fighting over whether such folk should exist is meaningless. Arguing that they're less than you makes you a douchebag and a bigot. Not to mention arrogant and petulant.
A transsexual woman isn't a violence against women. It's an individual trying to make the best of the bad deal nature handed out. A transgender person isn't someone to be shrieked at because they didn't choose a course of action you approve of. Don't like that "umbrella"? It might exist only in your head. No one is forcing you to be a part of it - argue against it. (Just try not to be a prick about it, 'kay? That just makes you look silly.)
No one needs, or should need, the approval of another to live as they see fit. As long as you're not harming anyone - who the fuck cares? Wear a sack for all I care. Call yourself a man-woman, a feminine man, a masculine woman, genderqueer or whatever rocks yer boat. (Can I suggest avoiding repeating yourself? For instance, saying you're a lesbian woman is redundant; a lesbian is a woman by definition. That's just an example, by the way...)
You don't have to like everyone, or anyone. Only fools demand that. What you shouldn't do is demand that others live the life you approve of. Because such demands only make you look like an insecure dick, are futile and you wouldn't want someone telling you how to live.
Is the guy who wears a tutu on a monocycle a threat to your transsexual womanhood? Your femininity? Your identity? Or is he just part of that wonderful panorama of life? (You might find it much more enjoyable to consider him part of the wonder of life. But it's your life; waste it on hating if you must.)
Why is it so important to you that others live as you demand and require, anyway? Don't you have anything better to do than screech and preach? Life's too damn short to be wasted on bigotry. It's a pity more folk haven't figured that one out.