I’ve never worked at Google, so while I can’t say for certain, I doubt the calendar has a “notify me about the juicy bits” checkbox. It’s certainly useful for me to know when my manager will be in the office or in some meeting, and if my manager marks the meeting “private,” I can know that he won’t be available at a particular time even if I don’t know what he’ll be busy doing.
If he finds it creepy that I know when he’ll be at the dentist, or be in a 1:1 with his boss, he needs to make sure the appointment is marked as private; I can’t do anything about it.
So, yes, I believe in this case, it makes sense to blame the people being tracked for publicity posting information that they didn’t want others to know.