libertarians are all about personal property, until it conflicts with another of their interests (often big business, but not always).
it's a quick way to tell what they really want. there's no really fundamental libertarian reason to not protect personal data as property; it's just that the vogue in pop-libertarianism right now is to strip consumer rights in favor of tech companies. why? well, maybe because pop-libertarians are techies, and they want that shit.
What I call the genuine form of libertarianism (small 'l') is about maximizing personal freedom, in the "life, liberty, and property" sense. The basic idea is that my right to swing my hand ends at the tip of your nose. Adult people should be able to do whatever they want that does not infringe on the rights of others, and then reap the consequences. For example: if you can manage to responsibly use any drugs you like, you should be able to; if you drive impaired because you refuse to do it responsibly, society has a legitimate reason to apprehend and punish you. Someone else who thinks drug use is always a horrible practice is free to practice that belief by not doing it themselves, but has no legitimate justification for persecuting a responsible user.
Privacy should be this way: your choice. I'm in favor of strong privacy protections in law because right now there is not much choice in the matter. If I want the Googles of the world to have my information, it should be because I knowingly, personally, actively, and deliberately gave it to them myself. Anything less is an infringement of my privacy rights. There is a clear intent behind burying such things in Page Y of a legalese EULA and that intent is to make it as difficult as possible to exercise this choice. A device that transfers my data to someone else on my behalf, by default, without my actively configuring it that way, shows the same intent.
There is a movement or an effort, more prominent and vocal the last several years, to deliberately misrepresent that all libertarian thought is the same thing as anarcho-capitalism. Observe carefully and you'll find that most any idea that, if popular, would threaten the status quo has multitudes of deceptive propaganda-technique-using PR efforts directed against it, the goal of which is to tarnish that idea in the popular mind. Most liberterian philosophies have a concept of inalienable human rights and include the desire for a government, the main purpose of which is to protect those rights. Regulation of business is necessary because otherwise, corporations will use their intense concentrations of wealth, market power, and political clout to infringe on the rights of individuals. This is legitimate and not some kind of control-freak idea or Puritannical fantasy of telling others how to live. Anyone who is against it and represents themselves as the only libertarians in existence (and not a particularly extreme form) is lying to you, it's as simple as that.