Having a mature discussion about it is not, ridiculing transgenderism as a concept/saying people cut off their genitals as a mental illness or to gain a competitive edge is.
I have no idea, whatsoever, where you got the "cut off thier genitals" from. It's as if you were implying that a biological male would have to undergo surgery to compete against women. That is not true. He/She would need to go through a probably long (depends on the sport) hormonal therapy of some sort but no surgery is required. You can have a penis, balls and compete against women, even at a top level.
Gender is about self-perception. Sex is about biology.
I couldn't care less about an athlete's self-perception. To each his own. His/her private life, none of my ******* business.
I care about unfair advantages and that is (or could be) related to sex, not gender.
Also the suggestion that it's "easy" for a biological man to be allowed to compete as a woman by "just saying you feel like a woman in a man's body" is completely and objectively disproven by the Caster Semanya situation.
The issue with her case is related to hormones as far as i can recall, right? But that is only part of the advantage. Height, wight, a lot of the muscle mass, etc remain.
Just look at Hannah Mouncey (biological male, 1,9 meters, 100 kgs, played for Australia's men's and female's handball team). She went through hormonal therapy but she is still just as tall and roughly the same weight which, at that level is a huge advantage.
And i am not saying it is easy. What i am saying is she has a very big and very unfair advantage.
The entire point of segregating sports by sex originated because of sexual dimorphism in humans. Gender was, is and should be (for this purposes, don't take it out of context) irrelevant.
Part of the point was also that the sex is something immutable and in the overwhelming majority of the cases, easy to verify (granted, for that small minority this will be terribly unfair and something should be done about it.).
This is an accident waiting to happen and will end up with a lot of people in tears.
It saddens me to a degree i cant eloquenctly express to say the following, but in this day an age, and given reactions like Oly's i feel i have to: I am by no means saying a trans person should be treated differently in any way. Again, how other people see themselves is none of my nor anybody else's business. In fact, i encourage them to act upon how they feel. It'd unhealthy not to.
But, long time ago it was decided that, in sports, we draw a line between two groups to appeal to different audiences and to level the playing field. That line was sex, NOT gender.
You could argue a new line or lines need to be drawn, and that is fine too. Lets discuss that. But what is happening right now is, not that. What is happening right now in some cases is that some people are using a new definition of what a woman is (self-perception) and applying it to what the rules said (sex). That is, again, an accident waiting to happen.