Most Helpful Guy
I think the biggest issue - and why there is so much aversion to it - is that it gets shoved down peoples throat that it is something normal while there are several people disagreeing with. In the example of Bruce Jenner it would be him getting some sort of medal for it. That's simply ridiculous.
Now why do people bully? They bully the weakest link. That's very often transgenders as even the transitioned ones have ridiculously high suicide rates which can't be explained only with bullying. To some extent humans are still animals who operate in hierachies with people on the top and on the bottom.
Needless to say that active bullying is wrong, but one should be allowed to disagree with it and state that disagreement.
To transgender itself: I, and quite a few others, think it is not something normal, but a mental disorder. The mentioned huge suicide rates among transitioned transgender surely have partly to do with the discrimination, but even more so with these people being mentally ill.
These people suffer from an identity disorder and being someone else, at least physically, seems for them to be the easy way out. It's the mindset of the grass is always greener on the other side.
It is the futile attempt of being different than who you are already on a biological basis. Reality though is that you are either a man or a woman - bar the few exceptions who have XXY or XYY chromosome and some other rare genetical mutations. You are a man or a woman and no amount of useless rhetoric, hormones and genital mutiliation will change that
Being biologically a man or a woman doesn't mean that all men display only masculine and all women display only feminine behaviour. That there are grey zones inbetween should be common sense.
The problem these days though is that people demand they are whatever gender they wish to be, including tons of made up genders (i. e. otherkins and the likes). This has nothing to do with being mentally healthy, but is at best attention-seeking and at worst a serious mental issue based on self-hate, lacking grasp of reality, cognitive dissonances and/or body integrity identity disorder imbedded in the hope that their mental health becomes better upon reaching the other side.
And in all honesty, for most TGs you can still see the men and it's offputting to a lot of people. Just that barely anyone dares to speak it out, because political correctness is the modern way of censorship and the majority of people are nice enough to not say it.1