I think the dev team has misinformed you again.
As everyone else has mentioned something has indeed changed, tested it myself and now can raid players that have much higher defense stats.
What you might have been told is that defense buildings are actually now 'working' as they were supposed to, for those new to the game and used to the way things 'worked' (note oxynoron) defense buildings appeared to have no effect. Also consider that these were added to the game for the most part and programmed by Funzio when someone with 100,000 stats was considered very strong....
My best guess is that a dev noticed that defense buildings weren't really programmed into the mix and had the bright idea to do so, but also stopped using a players defense stats. How IMHO defense buildings should of worked from the beginning is that they added a percentage to your overall defense stats and this could be mulitplied if you overlapped their defensive fields (that blue aura that pops up when you click on one). Then at least these buildings might have some strategic use in the game.
The other buildings do have a defensive value attached to them and that increased with the buildings level which is likely what you are talking about. Again the huge problem is that these values were applied way back when the game was first designed!
I honestly think I wouldn't have said the game is working as programmed or something to that effect because we've all grown used to the fact that the game has always been broken to some degree or was that comment intentional?