Mainly that means they won't sell to your local Guard or Reserve unit, or an active duty unit spending local option funds. Mainly for so called "self improvement" projects. So they go to Lowes or Acme/Ace or a regional or local business instead. The sad thing is that such local one time retail purchases most likely do not cause all the government supplier regulations to kick in. AFAIK, only if they have contract with the government do those "feel good" regulations kick in.
They'll sell to anyone that walks in. What they don't do is establish accounts for govm't agencies, because that means they would be subject to sertain govm't policy rules for contractors and suppliers.
LOL! I should wait 'till I finish reading before I post.