When someone transitions or tells you about their gender, here’s something important to remember: it isn’t about you.
The term I think you mean to use is “Medically Necessary”. Whether a medicine or procedure is medically necessary is a question best left to the patient and their doctors.
There probably isn’t a large difference in the numbers of (binary) trans women and trans men, but non-binary people likely outnumber either of the binary genders. The reason you probably think there is a significant difference in the numbers is because more attention tends to go to trans women.
A few weeks ago, I was having a conversation with a friend and she said something which has stuck with me ever since: "Be kind to your unhealthy self, as you are kind to your healthy self." I was gobsmacked.
As a trans woman, I might bring a different perspective to this question, as I’ve actually had the experience of being perceived and treated as a man, as well as being pressured to look and behave like one.
That isn’t likely. Hormones don’t cause our internal sense of gender - that’s something that is innate (built into us).