There's a delicate balance. I've worked on teams where it felt like I could never rely on one team member because he was using sick leave, personal days, PTO, and going to appointments at every opportunity. I don't hold it against him personally, but professionally it's hard to estimate workload for a given task if one person on a team of 5 is hardly ever actually doing work.

I've also worked on teams that, same as your friend, heavily implied that taking longer leave breaks were a no-go.

As with all things, it's a balance.