I don't even know where to start.

At this point I'd prefer you hadn't.

He made a plethora of points

There's a difference between rambling and making a point.

a response of "you sound high" is brimming with condescension and a general dismissal of his ideas

So, accurate and appropriate, then?

Just because you perceived it to be misogynistic

It was.

(which, let's be realistic, it made negative assumptions about women but calling that blatantly "misogynistic" undermines the meaning of misogyny and it's negative affects within society)

If it quacks like a duck...

doesn't automatically make his point invalid in the eyes of an argument.

It was clear he hadn't the faintest idea what he was talking about and knew next to nothing about the history of medicine, which happens to be one of my main areas of study. His argument was invalid, IIRC it was very late and I was tired of dealing with him.

You need to demonstrate the invalidity of his ideas if you're going to continue discourse, instead of just dismissing them.

I don't need strangers on the internet telling me what I "need" to do, thanks.

If you were going to make such an insult, you probably should have kept it to yourself.

How about you keep your pointless drivel to yourself, hm?

Also, you are NOT the arbiter of the meaning of your words.

No, just my own.

Words are words - you put them out there as a way to communicate an idea, but that's the limit to which you are the arbiter of them. The way they are received and the implicit assumptions created by them carries just as much weight. For example, myself, as a non-black, cannot use the n-word in reference to a black person, and then say "nonono, I meant it in a friendly way", or the word fggt in reference to a gay person, and afterwards say, "No, I meant that he's a dick. I don't care that he's gay". That's not how interpersonal communication works.

Mansplaining makes you look foolish, you know.

And I really do believe that you made an insult that extended beyond his argument.

I really do believe you're just lecturing me for not being nice on the internet and I do believe I don't care.

You were saying that the only way he could be thinking in such a way would be if he were high (which, btw, this doesn't really sound like a "high" argument), insulting his thought processes.

I will tell you what I'm saying, not the other way around.

Regardless of ad hominem or not, it was an insult that carried no backing but instead served as a dismissal of his ideas.

That's moving the goalposts, but I hope you feel better now.