Youngest hitman, only 15

Gun-control advocates claim that denying guns to everyone means that gun crimes will be stopped.

Thats false twice, or even three times if you look.

Here is a society with strong gun controls

Are you kidding?

Then you go on to passages I didn't quote.
But anyway lets deal with some

His stated point, and I do agree.

I agree, gun control does not stop gun crime, but only an idiot would claim it did so putting that up as a position to oppose is pure bull.
Effective gun control may reduce gun crime but the only way to stop gun crime is to make gun crime legal.

A positive case made for his argument. He may or may not be right, but he clarifies his argument and attempts to make his point. Where is the strawman?

Its in the wording again, he builds a false claim to argue against.
In this case "eliminates"
In each instance he is taking it to absolutes to make a "good" case to stand against but each time is instead making a "false" case to knock down.

Here we have a set of irrelevant jabs intended to minimize August's points

No, there you have 4 jabs which minimize augusts points and a response to Jims funny about prison "recreation" activities

If you look at the Darkfish exchange you can see it clearly, he takes a position and changes it in the same way so he can knock it, classic strawman