Their reason is "blaze your own trail", along with a shockingly poor excuse for system security. FD's complete lack of how to make a multiplayer game that makes any sense at all shines through here.
HOW TO FIX:
Make pirating very expensive bounty wise in non-anarchy systems, and make the system security react really fast to bigger bounty pirates. You could even make it so Pirates cannot re-buy using insurance in any system they are wanted. This will change how pirates operate, they will largely operate solely out of Anarchy systems (as it should be).
Now the problem is, how do you get traders etc to go through anarchy systems? Simple, you make the trade runs that have to go through multiple anarchy systems(or plot an extra 10-20 jump route to avoid all anarchies) very profitable, and the ones that don't, not very profitable at all.
There you have it, Piracy and crying about piracy is fixed! how simple was that? but will FD do anything? No.
Why? Well I think the designers are very begrudging of the DDF, none of them are their ideas or designs, and because of that, they don't want to implement them, they only want to leave their own mark on the game, but all of their own designs so far have been atrocious and lead to nonsensical game systems.