You could guess by finding a members last post.
But if you’re talking about the Users page, last log-in isn’t given there either.
Personally, I don’t consider my “activity” stats to be a privacy concern. I certainly wouldn’t want my email address or password to be available to members. Nor would I want my Preference Settings to be easily found (less a concern). But I have no problem with what shows on the User page or my Profile