It gets a little weird when you explicitly market them for a purpose, though. Flock doesn't advertise a fleet of cameras suitable for birdwatching or other random activities. They market them specifically for the collection and processing of PII.

By analogy, Google Docs isn't marketed for healthcare use. If you wanted, you could put a bunch of PHI in a Google doc and it wouldn't be their responsibility. They certainly didn't tell you to do that. However, if they marketed Google Docs as a great place to store PHI, yeah, then suddenly they're on the hook for complying with the relevant laws like HIPAA.

(Although in this case Google will sign a HIPAA business associate agreement with you and voluntarily agree to comply. They still don't market it that way, or at least don't predominantly do so.)