https://www.twilio.com/marketplace/add-ons/nextcaller-advanc...
Give it a try with your phone number. It'll provide your address (current and former), income bracket, relatives, siblings, children, etc, etc.
Guess what Facebook asks you to provide when initially setting up!?
"Name, Address, Email, Carrier, Line Type, Secondary Phone, Age, Gender, Household Income, Marital Status, Presence of Children, Home Owner Status, Home Market Value, Length of Residence, High Net Worth, Occupation, Education Level, Twitter Handle & Followers, Facebook Profile & Followers, LinkedIn Profile"
I do not speak for Fitbit, but I work for Fitbit, and I do not appreciate my employer being baselessly lumped in with violators of privacy.
It's not a baseless assumption that fitness trackers abuse access to people's private data. Maybe your particular fitness tracker doesn't today. That doesn't mean others don't.
And I am - for argument's sake - agreeing with the notion that privacy violation happens when the online service does something "wrong" with the data, not when the online service demands to keep their own copy, for their own uses, as a precondition to using the software.
History has shown that software that sends as much data home as possible can simply not be trusted with that data. Fitbit is one "innovation" or management team change away from further abusing the access to their user's data. I don't mean to coldly disregard the fact you trust your employer. But if I want an accurate assessment I can't care. Facebook employees trust Facebook.
Amusingly enough, so does Fetlife (NSFW). It's not outside the realm of possibility that even your specific kinks could be appended to that list.