Simple, trust no one. Get a no-reported-logs VPN, don't download anything that has a strange file size or extension, look at comments, look at the number of seeders if it's a torrent. If you can, join something like a private tracker where there's moderation too. If it walks like a duck and quacks like a duck then it's probably not the movie you were looking for and there might be a Trojan army inside waiting for you to let the duck enter your computer... That metaphor may have fallen apart on me...
Slowness and bandwith limitations are still an issue and it's likely that they will always be. It's already too slow to torrent large files over Tor and it also takes away the bandwith of other users. Tor also still doesn't support UDP connections, which may cause data leaks.
you do not have to use exit nodes. you can p2p with other tor users. piracy imo is important due to the censorship that countries can have on legitimate content.
Regarding your last point, I agree, however it is not as important and it does take up resources that could otherwise be used for the people who need it (journalists utilizing tor, victims trying to get away from abusers etc).
Especially given that there are still alternatives to piracy without tor, whereas there are far fewer alternatives for these people.
That said, you're still right, it's minimal. Overall though, options for piracy without tor are accessible and should still be used when possible. From my understanding, few circumstances arise where pirating over tor is a better method for you and for others
Basically, use tor for legitimate content to help make tor safer for others using it.
I added the word "reported" because I don't trust VPN providers to not keep logs, but ideally they should report that they don't keep logs and have an established history of not providing logs. Tor is really not ideal if you're trying to download anything large and you're still vulnerable depending on who controls the exit nodes.
Shenanigans are always possible of course so you shouldn't 100% blindly trust anyone, but all the available evidence seems to point to them being pretty legit IMO.