You’re asking people to not respect Microsoft because they’re doing something they’re legally mandated to do. If Microsoft takes the route many have argued for here (namely, reject the DMCA request as it’s invalid) and the DMCA request ends up being found valid in the courts, Microsoft loses their DMCA safe harbor protections and open themselves up to multi-million dollar lawsuits. Sure, if they’re right, then they’re in the clear, but when their business is at risk of being killed if they’re wrong, they’re going to err on the side of caution.
It’s easy to stand at a distance and mock those who do something we disagree with, but when you’re actually in that situation, your tune is going to change very quickly. A bad example, but if you’re getting mugged, sure, you could fight back, but your life is on the line.
The safe harbor under Section 512 applies to takedown requests for content copyrighted by the person issuing the notice. I don't think there is anybody asserting that the RIAA is the author of youtube-dl and thereby eligible to make a claim under that section.
I would also be curious to see you cite a case that says that refusing a takedown notice in one case costs anyone the Section 512 safe harbor in all other cases where they continue to execute takedown notices, since that would be oppressive and ridiculous.
It’s easy to stand at a distance and mock those who do something we disagree with, but when you’re actually in that situation, your tune is going to change very quickly. A bad example, but if you’re getting mugged, sure, you could fight back, but your life is on the line.