Certainly a point of view, with a grain of truth.
However, what worries employers is any residual influence that a union might still have over any process that affects its members.
Thus, to tie a union into a non-disclosure agreement, whereby they weren't allowed to tell their members what their new employment contracts might be, would be heaven to any HR department or commercial section wishing to tie up a nice deal with an outsourcer.
So the union is damned if it does, damned if it doesn't, which is just fine and dandy from the council's and IBM's shared point of view. At least by not signing up to the NDA the union has some limited room to manoeuvre.
But hey, it's easier to characterise anybody you despise with the suffix -tard rather than to appreciate the difficult job they're trying to do on behalf of other people.
(IT because that's usually the first to be sold down the river by people who understand the price of everything, and the value of nothing)