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.