That is my understanding too. We do not have a disagreement on that.
> he got a copyright strike, which means a DMCA takedown
Here is where we disagree. A youtube copyright notice / copyright strike is not the same as a DMCA takedown.
The DMCA takedown process as described in the Digital Millennium Copyright Act Title II. Online Copyright Infringement Liability Limitation Act provides more rights for the content owner whose work got maliciously or mistakenly taken down. They have access to a counter notification process and §512(f) makes those who knowingly materially misrepresent content as infringing liable for damages. You don't have the same rights and affordances with the youtube copyright notification system.
It is similar. If you squint it looks the same. But it is not the same.
> A youtube copyright notice / copyright strike is not the same as a DMCA takedown.
Yes it is. YouTube doesn’t magically get to ignore the DMCA, so their process is built around that (along with layering Content ID on top to allow for a middle ground where videos can stay up but redirect some or all monetization to the copyright holder).
If you click through the link I posted above, you’ll get to this page which shows the complete process, including the counter-notification step: https://support.google.com/youtube/answer/13823830 Do you have reason to believe 3blue1brown can’t file a counter-notification in this case?
Does YouTube's system also make a malicious complainer liable for damages? The DMCA does. Here's the relevant section of the law mentioned by krisoft:
(f) Misrepresentations.—Any person who knowingly materially misrepresents under this section—
(1) that material or activity is infringing, or
(2) that material or activity was removed or disabled by mistake or
misidentification,
shall be liable for any damages, including costs and attorneys’ fees, incurred by
the alleged infringer [...]
Probably not. Youtube has their own system which is not DMCA claim based.