You do. IPFS isn't Freenet, you're not contributing to some global pool of amorphous storage.
It's just like running a webserver, but with content-based addressing, the possibility of having multiple machines provide the same content and much more convenient mirroring than over HTTP.
If you start an IPFS node, it'll remain empty until you upload something, or pin (copy) somebody else's content.
I think your node might also cache requests you make to it for some time, but that's also something that's a result of you asking for it.
So, if the FBI comes to arrest me can I just get away with that? "Sorry guys, I do have an IPFS server but I had no idea it was distributing illegal content to the world. Can I go now?"
In Freenet you contribute to a global pool of storage, and end up storing and transmitting whatever the network happens to need. Freenet is intentionally obscure about it. The archive is encrypted, there are no logs, there's no way to list what your node contains, and storage is probabilistic making it hard to determine if something is there because you asked for it, or it passed through your node.
Tor also tries something similar, and has premade explanations to give to authorities if they ask about your exit node.
But those are specifically built to try to work with that case. Stuff happens behind your back that you have zero involvement in besides providing a piece of infrastructure for the network.
In IPFS on the other hand you make a personal, intentional choice to mirror or upload something.
I want to slightly clarify the case of Tor: while many people historically thought that running an exit node on your own network (that you also actively used) might create ambiguity between your own activity and strangers' activity, this is not really considered correct or advisable. One reason is that a fairly naive local adversary monitoring your connection at only one location can still tell whether particular outbound clearnet connections do or don't correlate with inbound Tor traffic. That allows distinguishing activity by a local user from activity by a Tor user that's proxied through the exit node.
