IPFS makes a point of not storing data that has not been requested explicitly by that IPFS node, so IPFS node operators might not carry the same plausible deniability that something like FreeNet carries. As a brief example, I'll show you how to get IP addresses of IPFS nodes serving particular content. There's a ton investigators can do once they have IP addresses.

Here's the IPFS hash for the poster of a particular movie put on DTube: Qmb4zt1i3dxQMbpYprdeMqZeLoT6r64gcMmUHhV9D7AQVY
I'm not going to link to the video stream itself - that's an exercise for the reader, but the priciples are the same.

Here's how to find a list of nodes hosting it:
ipfs dht findprovs Qmb4zt1i3dxQMbpYprdeMqZeLoT6r64gcMmUHhV9D7AQVY

Then, from that list we can get IPs for the nodes serving that content:
ipfs dht findpeer [nodehash]

There's some other things about the way IPFS and DTube are built that make finding viewers and content hosts much easier than torrents too. If I could figure this out in a few minutes, you can bet some investigators can too.