I'm not sure if it's so much resentment as an implicit rewriting of the contract of employment. If I'm contracted for 40 hours a week, but the only people being promoted are the ones who "voluntarily" work 80 hours a week then the revealed policy of the employer is that everyone's being paid to work 80 hours a week, or 60, and if you're doing what was agreed to in the original contract you're slacking off.

You see this plenty even in less extreme examples, my old company had yearly awards for outstanding performance, and there was a clear pattern that the story of why the person had won almost always involved some personal sacrifice in service of the company. No one was winning awards for just being good at their job, showing up every day, and being a value to the team. You had to take a break from your vacation to get on a meeting, or work 2 weeks straight to get the award.

I'm sure the well-meaning among leadership (which I do believe was a decent amount of them) saw this as more of an apology. "Here's something to recognize that you did something you shouldn't have had to do". But functionally, it was creating a culture where you needed to abuse yourself in order to be recognized.