I support free software, but that doesn't mean dangerous offensive software shouldn't be regulated...

A currently viable virus should not be able to distributed freely without any regulation, even when it is licensed under GPL; the fact that viruses can be used for defensive purposes (hacking a hacker's laptop to get ransomware pass code, or hacking scammers to warn victims etc.) also won't change that.

It is the same way with lethal poison, just because it can be used in defensive ways, doesn't mean it should not be controlled.

I watched the video. He says that if you support FOSS you should support guns, but never once advocates for guns to be free.

He says the problem is that politics are tribal, and people are simply in their corner, cheering for their teams - without acknowledging that there are Americans that want different levels of gun control, and there are reasons that people want gun control outside of tribal politics, and there are Republicans/conservatives/gun enthusiasts that have nuanced opinions, and support things like red flag laws and certain gun control policies.

Having the right to have a mass killing device is never required.

Yes, there are open source firearms. there is even 3d printed designs for an MP5 the youtube channel Print shoot repeat showcases a lot of them.

You can't install Arch by good sharpshooting skills.

A bullet tends to destroy the drive.

"Guns don't kill people rappers do, from Bristol zoo to B&Q"

The author of the Bazaar and the Cathedral, an essay about open source development, wrote a lot about gun rights too, like explaining banning automatic weapons was dumb, as a good shooter would make more damage with a semi automatic.