Its also illegal to give away vegetables if you have a garden, or milk if you own a cow , or take your neighbor food if they are sick if you don't have a license from the health dept.
All that is true, and I disagree with all of them, including requiring an FFL for Ken to do the work to make a couple bucks. As a Gunsmith, I think that the ATF requiring me to record transactions like coming in and out like a sale in a bound book is crazy, also requiring a Manufacturing License (07) for gunsmiths that drill and tap a receiver for a scope is crazy. I also think the FFL license requirements are B.S., You have to prove you are doing it as a business and also have to have approved zoning before the ATF will sign off, that is tough to do if you are working out of your house.