You are the example I was pointing out. At no point did I say anything about a company account. This happens on all windows machines. You can for example login to a machine acting as a server simply to use the Microsoft store to install something only to have it start syncing your files to that machine or even intermingle them and then force you to go through a tedious clean up process.

I have seen grandparents accidently lose all their files because they didn't know their files were being synced and then when they removed the Microsoft account from their machine suddenly their files are missing. Situations where they were told by support to logout / login only to lose all their data. These people take weeks or months to finally get someone's attention about the problem irl and these are precisely the types of people who will now be losing data because of the cavalier attitude from the so called experts.

I've seen all sorts of situations. The problem is that after updates OneDrive tends to turn itself on or enable syncing when it was previously disabled without telling you. Or you use a Microsoft account to install something through their store and bam suddenly the local drive is intermingled with yours. It's a mess precisely because it's built in.