The more interesting part is the second half, in the smaller print where the author addresses his teammates. He uses words like "respect", but what he's saying feels contemptuous and passive-aggressive. That's the real tell here. Well, that and the suggestion that he doesn't believe in what he's working on. No wonder he feels like checking out every day.
Does it matter what time someone leaves? Only if people feel it does. What matters is that a team be aligned. If there's disharmony, work it out. If you can't work it out, change the team. Writing a "manifesto" is not working it out (though it might start a real conversation).
Personally, I want teammates who are passionate about doing great work. Come and go whenever works for you. But passion doesn't get turned off like a light switch at the same time every day.