I dislike seeing anyone lose their job because they are transitioining. However, I question her methodology if indeed she "showed up at a company picnic wearing mascara, eyeliner and white-tipped acrylic nails". If that's what actually happened, and there was no forewarning nor HR-related conversations re her transition, then she was cooking up a recipe for failure. A responsible transitioner does not "show up". She (or he) works with the responsible HR representatives and shows respect and consideration for her colleagues and co-workers by socializing the change and orchestrating that work-place tranistion in a manner that shows the company she has both her AND the company's interests in mind.
I DO NOT condone her firing, but I strongly question her methodology and lack of thoughtful consideration of her company and its employees.