Honestly, the slide deck to me looks like a positive and important correction from a company that's been too lax and directionless in its management (this is an inference - I don't know anything about Meetup specifically). It's not contemptuous, it's honest and direct. Most companies would not be so honest with everyone about seeking a change in direction like this.
> Past: We debate too much without defined decision makers and don't act on decisions
> Starting now: Clear decision makers end the debate, communicate the decision, and act quickly
> Past: We wait too long to take action when someone isn't meeting expectations
> Starting now: We take actions fast and say goodbye when someone isn't meeting expectations
Someone who has been a manager for years should know how poisonous it is if people can't make a decision because they are overly focused on consensus and there is no clear decision-maker; and they should know how poisonous it is if people keeping debating the same decision after it's been made, and don't get on board with implementing it.
Lack of accountability is similarly poisonous, and lack of initiative is problematic. Letting poor performers stick around too long is poisonous (it demoralizes everyone else). These and other principles in the deck are part of the basics of good management. I don't see much to object to in here.
The slide deck makes it seem like this is an organization with a (management) culture that's gotten fairly far off-track from focusing on building a successful, thriving, growing business. Senior leadership is trying to course-correct. This slide deck is a nice way of communicating "we have a serious culture problem and need to fix it".
Managers who are achieving success and have not fallen victim to these anti-patterns probably don't need to change anything because they already understand the lessons embodied in these slides. Hopefully those managers are rejoicing because their ineffectual peers are being steered in the right direction now.