[bskap]

The problem is with the incentives: if the recipient of a DMCA request doesn't immediately take down the target, they become liable for any copyright infringement.

While Google would probably win if it came down to a lawsuit, the two options they have are to take it down and let the site operator dispute it, or go to court to defend the actions of a group they're unaffiliated with. The obvious choice for pretty much any group is to take it down.