If you dig deeper, its not about piracy - its about control. What do the majors get from Spotify/Apple music that they don't get from YouTube? If the majors don't like their deal with Spotify (whether its 80% of the revenue, or no free listeners), the majors can walk, and if any of their music appears on Spotify, the majors can sue them out of existence.
With YouTube it's different -
1.) YouTube is the largest streaming site so users will always look for music there
2.) Anyone can upload music to YouTube
3.) YouTube isn't financially responsible when someone uploads infringing material.
These 3 factors mean, if the majors decide they want 80% of YouTube's revenue rather than 50% and YouTube walks, there is a chance (more like a given) that someone will upload Taylor Swift's new album on there pitch shifted by 13% (to evade content id), and will go on to generate millions of views. And since YouTube is protected by the DMCA, the majors can't sue them out of existence. That's why the majors hate the DMCA, as it applies to YouTube. There effectively isn't a "scorch-earth" policy for music on YouTube, and the majors can't leverage their army of lawyers to force YouTube to submit to them if "scorch-earth" fails.
Now I doubt "we need to kill the DMCA so we can sue YouTube for billions" is very PR-friendly, but "muh piracy" always is.