Earlier quoted context omitted.
> fill it with full length DVD rips As long as users do it, and the site takes them down when requested, I'm pretty sure it's legal under DMCA.
As stated in your parent and elsewhere, Mega rarely responded to DMCA requests.
I've had companies take down content after a DMCA notice but never inform me they have done so; there is no requirement for them to do so.
I assume you're referring to the latter meaning though--that they left up infringing content after receiving notice. If they did that then they're in deep. ...As long as the US has jurisdiction to prosecute, which they probably do.