The thing is; only someone who's been living in a cave wouldn't know the (well-founded) animosity to the Sun in Merseyside. And the reaction to staff being asked to be involved in promoting it is entirely predictable.
It rouses such intense feelings that this was absolutely bound to cause the reaction it did. Any management who had a clue would have seen it coming a mile off. Therefore its as much to do with bad management, as it is to do with bolshy employees.
These people have clearly decided, on a matter of principle, that theres a line in the sand they won't cross. In this case being involved in actively involved in promoting a publication they rightfully despise.
How would you feel promoting an organisation that had labelled your friends or family (completely dishonestly) as drunken thugs who only had themselves to blame for their own deaths? You'd be happy with that, would you? And just get on with it, thinking "oh well… its a commercial contract negotiated by my employer, so I best be on my way"