Some told me they felt wronged by the company somehow. For example they had experienced bullying, or didn't get promoted when they felt they should have been, or they had contributed something and then it got cut from the product, something like that in most cases. Now didn't feel they owed the company anything. Yet others said the pay is not enough to really get them invested in the work.
The fact that they needed these excuses tells me they felt what they did to be morally wrong and didn't really want to be dead weight.
I personally have done a few projects that turned out to be purely compliance based, and had no merit whatsoever. I remember the feeling of wasting my life to be absolutely soul crushing and I have been avoiding that kind of project as if my life depended on it.
Your mileage may vary.