Totally agree. Sucks that criminals sell weapons to other criminals.
However, if you think that buying a firearm legally is easy... look into this: https://news.yahoo.com/reporter-tries-buy-gun-walmart-083700384.html
or this:
https://www.nicsezcheckfbi.gov/help/ENG/New_NICS_ECheck_User_Guide.pdf
Doing it LEGALLY is quite prolonged and intensive whether you attempt to purchase from a store, pawn shop or gun show... even for a handgun. Though, if you attempt to purchase from a pawn shop, they can release the firearm if the background check is held for more than 5 days (it's up to the owner of the shop) - fun fact.