So? It WAS perfect legally have them back then until around 1965. You could order bunch of em though mail order and as much as you want. Because of drama with JFK, Government get more fear, banned bombs, then tried gun control, and so on.
Having 50 lbs dynamite is far better than having 50 lbs of flash powder which is also legal until sometimes 1966. Flash powder has much much higher flash point than dynamite.
Point is, you never know that you'd be sitting right above anything. It is not like a terrorist thingy, need not to be concern.