It isn't legal. And, in my opinion, it's morally wrong. I guess the Rolling Stones will get buy if they miss out on a few dollars from removed DRM. But it's their work and they want to protect it from misuse. No copyright = public domain = use it without regard for whoever's work it is.
And forget putting the work up on YouTube. I've put up some very obscure tracks (which I credit in the closing crawl). Often YT marks it as "artist reserves the right to monetize the video" because their work is in it. I've got no pride on the matter, but it demonstrates that YT does check content. And they do block gross copyright infringement.
Additionally, production companies have people who look for violations, and lawyers that send unpleasant "cease and desist" letters. Once someone's on their radar, there's a good chance continued violation won't result in just another letter.They obviously don't catch every violation. But being the one instance that's caught isn't a good experience. Think this is an urban legend? My wife has sent out more than one "cease and desist" letter as part of stopping copyright infringement. And pursued continuing offenders in court.
Short answer: don't pirate DRM material or at least keep it to yourself.