Frogman,
Do you really think they care how upset you are with the management? Haven't you figured out how it works after all these years? There are two things they want to find out with this survey. 1) How many would actually leave if they screw you bad enough, with all honesty and no peer pressure and a unique login. 2) How much they could get away with in future negotiations.
I totally think they will take this survey seriously, they paid good money for it so they definitely want the results. Just not every single question they asked you though, definitely not the one about how happy/unhappy you are. Your happiness has no real value in their spreadsheet, everything else in that survey does, and that's the only thing they care. Remember, you are just a number that costs them more than others in order to get the aircraft from here to there.