This is the work of most of medicine and science. It's not fighting. But understanding what the correct definitions are is foundational to being able to talk accurately about the phenomena. There's a lot of work that goes into understanding psychological disorders from various different perspectives, including neural anatomy, genetics, behavior etc.
> what to me mostly look like different maladaptive coping mechanisms with very similar underlying causes and very similar treatment options.
The existing disorders these days do a pretty good job of not being too overlapping with respect to cause or symptoms. They are frequently confused with each other either due to incomplete information at the time of diagnosis or due to practitioners not being familiar enough with the latest research. Autism I know is one that gets frequently misdiagnosed as bipolar disorder or anxiety.
There are comorbidities, but those comorbidities are sometimes due to things like misdiagnoses.
> To you, things seem to be either "pseudoscience" (on what grounds?) or "scientific"
I'm not sure what you're driving at here. But science and pseudoscience are different.
> what you write sounds very much motivated by your own political beliefs
The only things I think I've written about my political beliefs on HN are that I'm opposed to political violence, I value democracy, and I value truth and the pursuit of truth. I'm not sure what you are trying to say here.
> And, why shouldn't people be motivated by their beliefs? They can still be good scientists too.
You can't serve two masters. Science is about what is true. If one believes in a sort of "higher truth" that they make science subservient to then they're not really doing science. That goes for whatever they take the "higher truth" to be. Often it's a religious commitment, but it could be other things.
> dismiss Freud as "pseudoscientific", where he expressed very clearly that he wants people to challenge his theories ....
Science isn't about things like having people challenge your theories. It's about making predictions, having on objectively verifiable method for checking the outcome of the predictions, assessing how and why the predictions went wrong, etc. Freud didn't do any of that.
Freud's theories and whether they are scientific or not has been written about a lot. I think it's probably covered in a lot of intro do psychology books. But you can also find web pages about it.