“Ghost guns can be purchased online from thousands of different websites without a background check.”
That’s a Federal Crime! While it’s perfectly legal to build your own firearm, you have to perform all the tasks associated with turning those parts of the firearm that are considered to be “the firearm” by the ATF into functioning pieces yourself. Furthermore, you cannot sell what you make for yourself.
What people are purchasing are “kits” that contain non-functional part (s) that you must convert yourself.
Just more journalistic stupidity on display.
Not true. So long as you're not making and selling them in quantities that would demonstrate you're really doing it as a business, it's perfectly legal (depending on your state laws) to sell one of these guns just as it would be any other gun you own and no longer want. The ATF does suggest you serialize guns you make, supposedly for establishing ownership should they be stolen.