The first paragraph is not really relevant to this thread. Yes, people should be fighting back. Sure. Things are happening regardless though.
People have been making stuff since stuff was made, or do you think everything ever was made from a company's factory?
Making things to function at home is great! We should do more of that, and more FOSS. However, driving on a public road requires that you meet certain conditions. You can't just throw a lawnmower engine on a set of wheels and call that enough. Yes, it'd drive, but it wouldn't be legal. There are many types of vehicle that function that are not road legal. It is possible to meet those requirements with something built at home, but it requires serious technical knowledge, skill, and equipment. It also still has to conform to state and federal regulations.
Also, I agree with this, assuming it isn't abused. I'm an Anarchist, but even I see the need to regulate vehicles people should be allowed to drive. We're driving tons of steel at each other at high speed, just inches apart. You're subjecting others to the danger you create. If your car breaks and swerves into incoming traffic at 60mph, that isn't something the other party willingly consented to. It is the government's role to protect people from harm. We go too far usually, but it needs to exist. I don't want to be on the road where a bunch of homemade junk that hasn't been regulated is driving around.