This transgender thing irritates me extremely. When physically, someone is a male, but thinks he is a female (and vice versa)? And then some go great lengths to actually physically alter their bodies with hormone therapy and surgery. I don't know what to think of that. But it sounds to me like facilitating psychological issues. If someone thinks he needs a vagina and breasts to be eternally happy, isn't that the same as someone who thinks he needs to cut his arm off in order to be eternally happy with himself? Good thing I don't have to decide on that.
Well, people who shoot their mouths off about serious medical issues in a way that can be hurtful or harmful to others without any knowledge or evidence to back up their assertions irritate me extremely. Why don't you decide on how to discuss things in the future without coming off like a total jerk.
Okay, if it makes me a jerk to say I don't know what to think of it, and then ask a question about it, then so be it. I actually was hoping for a serious answer. Why is it not a psychological issue?
Let's not pretend you came into this thread with an open mind and an attitude free of judgment. You started off saying it "irritates [you] extremely," as if your personal comfort with something is the foremost concern.
Without giving you a complete history of trans issues, the reason it's not considered a mental illness is because treating it as one doesn't work. You cannot convince someone who considers herself a woman trapped in a male body that they are, in fact, just a man with a mental illness. That approach was tried for decades and it simply doesn't get results.
So, what does work? Taking a trans person's gender identity seriously and assisting them with transition to whatever extent they are comfortable with. Not everyone opts for surgery to alter their genitals, nor do they all use hormone therapy, but those are all options that are available.
Telling a trans person to stop being trans is about as useful as telling a gay person to stop being gay.