Piracy is not stealing, it is copyright infringement and there are important distinctions. I would never say piracy is "good" but if someone copies a game they never would have bought, nobody is losing money. Of course, someone who copies a game isn't necessarily honest about whether they would have bought it or not...

if you believe piracy is wrong then using emulation to play pirated ROMs is also wrong. There is no distinction. Companies can always make money on IP that they own by re-releasing older games and they often do so in various collections or even more commonly now as digital downloads. Ocarina of Time for instance was available to play via the Switch.