It seems to me that part of what is missing in this discussion, is a recognition that unconditional positive regard is understood as a necessary and important part of the way a mental health professional interacts with clients. Statements such as the ones Peterson is being criticised for, made so very publicly, would absolutely undermine some clients' confidence in the unconditional positive regard that underpins their emotional safety in the therapeutic relationship.
I understand what you're saying here, in theory, but where's the limiting principle?
What's being branded as "emotional safety" and "disrespectful" is something of a moving target, and one that seemingly aims to cater to the sensibilities of one particular political faction.
If a clinician gives their honest opinion about something that they honestly see as a problem, that's going to occasionally cross some peoples' comfort zones.
Per the links I posted earlier, there are already people (and not just a few randos on the internet, but major publications) advocating for ideas like "a doctor talking with an overweight patient about their weight is disrespectful", "doctors should avoid bringing up weight if it makes the patient uncomfortable", etc...
In this particular case, if studying the psyche of a person who identifies as non-binary is the aim, and it's supposed to be somewhat scientific, then it can't be done rigorously (or honestly) under the conditions of "
you have to use my pronouns, and you have to acknowledge first and foremost that this is real, and a good thing that's to be celebrated, and not just an outgrowth of a mental health problem...otherwise, it's an assault on me"
If a clinician was working with the topic of addiction and alcohol use disorders, that'd be like people demanding "you have to say that drinking isn't a problem, and you have to acknowledge that drinking is completely normal, otherwise, people who like to drink will be offended and won't feel emotionally safe"
...that's not going to end up being a sincere delving into the subject if the clinician is being given the marching orders of "we'd like you to study this topic, but here is the one approved conclusion your research is allowed to come up with, and here are the 20 conclusions that are strictly off-limits"
And that is sort of what's happening with the fields of psychology & sociology...basically the demand is for "conclusion-first" research on certain topics, where they're working within the framework of "here's the approved conclusions you're allowed to have on this topic, don't color outside the lines or there will be professional consequences".