I don’t follow the logic here. There seems to be an implication of ulterior motive but I’m not seeing what it is. What aspect of ‘privacy’ offered by a VPN do you think that Reddit / LinkedIn are incentivised to bypass? From a privacy POV, your VPN is doing nothing to them, because your IP address means very little to them from a tracking POV. This is just FUD perpetuated by VPN advertising.
However, the undeniable reality is that accessing the website with a non-residential IP is a very, very strong indicator of sinister behaviour. Anyone that’s been in a position to operate one of these services will tell you that. For every…let’s call them ‘privacy-conscious’ user, there are 10 (or more) nefarious actors that present largely the same way. It’s easy to forget this as a user.
I’m all but certain that if Reddit or LinkedIn could differentiate, they would. But they can’t. That’s kinda the whole point.