Because conspiracy theories are self-perpetuating. They have no basis in truth but what people "wish" had happened so they could blame the ones they WANT to be responsible.
As my brother said.....""Can the Government guarantee the dikes wild hold next time?" Give me a break....NO! The sea wins every time." Nuff said. But enablers and those who wish to place blame will never understand that nor do they want to understand the REAL truth.
The October 2003 National Geographic (I believe that’s the right month/year) had an article on New Orleans and the system of walls and levees in place to protect this sub-sea level city. It stressed that this system would fail in the event of a major hurricane, Category 3 or above.
I don’t believe the people who perpetuate these theories read an awful lot.