Because what you are requiring there is that women give validity to the pretense that a male can be a woman by a trick of language, and coercing with the 'be kind' (and don't be disgusting) bit.
A transwoman is a male who prefers to be named and treated as a woman. I do not hold the belief that they are in any way a subset of women, they are a subset of men and that is fine.
There are limits as to how far the pretense that some people would prefer in order to protect the feelings of TW can be taken for their benefit without entering into misogyny and oppression of women. The line was very much left far behind this weekend. I will not collude in this kind of thing any longer. Nor co operate with demands for respect and kindness from a group of males that emphatically do not reciprocate any kindness or respect to women, but in some cases bear signs advocating their rape and murder.