You might consider that you drank the rights kool aid/carricature a bit too much — and if you grew up in a world where trans people were portrayed as "abnormal" that might have something to do with you being receptive to it. The US left is already pretty moderate. The Democrats
are a centrist party by most of the worlds standard. Where I am from they would be the conservatives, and I am from a deeply catholic province in the Alps.
That means your right is just so very far right, that centrism is no longer a useful term in the US.
That being said, people "become" trans just like one "becomes" left handed: You discover it one day and go: "Oh shit, I am trans/left handed". There is nothing you can do about it. Sure you can hide it from society to avoid scaring them, but that is very unhealthy for you.
There was a long time when kids had to hide their left handedness because it was seen as "abnormal" by the right handed majority. And then when it became medically irrefutable that it is natural and that forcing right handedness on left handed people can have serious medical and paychological sideffects left handedness became normalized. Suddenly there was a "rise" in left handed people (in fact however the left handed people existed all the time, they were just hiding it). The number of left handed people then stagneted around it's natural occurance rate of roughly 12%.
The whole trans discourse is a discussion about a very similar phenomenom. People are gay, trans, asexual, left handed and there is nothing they can do about it, as they have been born with that trait. Now the flipside of that is that you can't get gay/trans/asexual/left handed by being "exposed" to it. Either you are already trans and hide it from yourself so well that it probably alreasy takes a psychological toll or (much more likely) you are not.
That being said, what is the "trans ideology of the left"? I can't speak for the US, but a few thoughts:
1. to speak of "the left" is... interesting. Last time I checked they all had different views on the same topic. So whom do you mean, or are we speaking about the left as the right paints it?
2. At least the left people I know don't do anything more than say: "If you are born trans, that is okay, we accept you." I guess if you agree with the scientific consesus that being trans is not something you learn, but something you are, then this should be a acceptable view to you too.
3. Because most trans people are not treated well by the society around them, the left often demonstratively gives trans people special exclusive spaces or helps them in ways they pobably wouldn't help a straight white guy from an upper-middle class background. As any political solution this can either solve real problems or be pie in the sky, but hey they are trying to help.