Sometimes the idea of arguing reminds me of xkcd: Duty Calls (which kindly mocks that practice).
Conversely I think that Buddhist doctrine is more like this -- i.e. "Others will [...], but we will [...]".
A young Quaker -- i.e. a "pacifist" -- once told me, "I'll discuss anything with anyone; but if it turns into an argument then I [...] and walk away."
I think that gives you an option: to discuss, or maybe comment on a topic (perhaps to offer discussion) -- without a counter-productive argument that escalates into harshness.
When I think about "harsh speech" that I've very occasionally seen in comments on this site, I think that one of the remedies is:
- To say what you need to say (e.g. to comment on an answer) but preferably without being harsh.
- Someone might then reply to that comment.
- At this point, don't forget you have a choice:
- If your reply would continue a friendly discussion then why not
- If your reply would be an argument then maybe you shouldn't -- you said what you had to say in your first comment, maybe leave it at that.
There may be a difference between in-person "speech" and on-line "writing" but I'm not sure what to advise about that.
I can't easily reply to the part of your question about insanity.
My experience of schizophrenia is of years of thought disorder (both, "content-thought disorder" and "formal thought disorder"), as well as of years of lucidity. The question (the OP) seems lucid, it's not a word salad, and my experience may not be applicable to your situation.
Even so, for what it's worth, my experience as a participant or care-giver is that it's essential to remain kind.
- Discussion can be frustrating (if you're trying to persuade someone who won't "comply").
- It can also be disorienting (to experience a disconnect in the "meeting of minds" that you might normally expect in a discussion).
- Sooner or later it might be tempting to try something else -- e.g. "if kindness doesn't work then how about harsh speech?" -- but I think that's most likely a mistake, and you need to find another option (maybe talk with someone else instead).
One last piece of advice is, I think that maybe professionals don't indulge (don't participate in or encourage, but maybe also don't dispute) a person's fantasies, but instead interpret what they say in a way that keeps the conversation on "common ground".
For example, hypothetically:
- Psychiatrist: "How are you feeling today?"
- Patient: "I am the Supreme Being."
In reply the doctor needn't discuss the patient's statement that they are God, but might instead reply with something like, "So, you say you're feeling good."