Linux is commonly used in the communications systems, like on invidual radio "stations". Propably used everywhere where high confidentiality and security is required.
I agree, and as other comment mentioned: foss seems to appeal more to the left leaning. It'll probably get more balanced with time, though not like I want more rightwing circlejerks but that the extremes would get kinda buried under the masses of sane people.
Yes, though there are some prebuilt binaries for large packages. I use gentoo on a desktop and updates don't take too long, minutes. Big updates that cause lot of packages to rebuild can take hours.
Linux is commonly used in the communications systems, like on invidual radio "stations". Propably used everywhere where high confidentiality and security is required.