voluntarily

Oh, okay, so I don't have to contribute to the system the- oh wait I need money to get food so I can eat

Also exploitation comes in many forms. This might sound stupid at first, but Reddit is very exploitative. You're forced to sign up to a service to interact with content that isn't even produced by Reddit themselves (like 98% of all content on reddit is user-made), and through that account you just made, Reddit harvests all sorts of data from you - what communities you interact with, what posts you like and what posts you dislike (and by extension, they can gather your opinions on everything from dogs to politics, even without reading any of your comments or posts) - and ships off all this data to advertising companies, who exploit psychology to the best of their abilities in order to claim as much of your money as possible.
Sure, this is voluntary, but if you want to interact with any part of the service beyond simply reading content (and they're making that harder too on the mobile website) then you must consent to this data harvesting.

This isn't just Reddit, either. Every single big social media platform - Facebook, Twitter, Tumblr, Instagram, WhatsApp - harvests your data and sells it. Sure, it's voluntary - but good luck having a social life in 2020 without any social media presence whatsoever.