Dude, of course the NET shouldn't just blindly value wins and losses since that's out there in plain sight for everyone to see anyway.
We use advanced stats to get a sense of a team's efficiency normalized for the strength of schedule. It helps us separate teams with similar records.
Considering Duke is #5 in KenPom, #7 in Sagarin, #9 in KPI, #2 in BPI, #5 in Massey, the #6 NET ranking seems right in line.
Again, if UK ever actually started blowing out "inferior" teams, their advanced stats rankings would go up. This isn't rocket science.
Luckily for UK, since their W-L record is good, they"ll get a high seed anyway. Its worrisome for its NCAAT prospects though.