That doesn't make it an acceptable reason to do so. They could probably google my home address easier than get LinkedIn to disintermediate themselves, but a barrage of recruiters at my doorstep would not be appreciated.
The truth is they probably don't know. These days the process of guesstimating an email address behind a LinkedIn profile is highly automated. Very often what a recruiter see on their dashboard is basically a list of potential candidates' LinkedIn profiles, paired with a list of plausible email addresses for each of them (with no indication of how the bots got them in the first place).
Automating a behaviour I disapprove of doesn't make me disapprove of their actions less.