@maloki Mastodon doesn't, but individual instances can. Also, the protocols allows a great deal of access to data that you otherwise would need to buy.
So, while you are saying is true (and indeed one of the main reasons I use this system) it does not mean that your activity on the network won't be tracked.
Just remember to not post things you don't want to be public and linked to your identity (unless you go through the effort of being anonymous using Tor or such service)