Ok if these social media giants are authenticating LEOs by origin email only, without benefit of GPG, or secure token, or whatever, then they are stuck on stupid, and deserve any hacking they get. Ouch.
I don't think most law enforcement agencies have any second factor to authenticate themselves online. And it's not the social media companies that suffer but their users whose privacy is being violated.
but maybe you're right and this problem won't be solved because the person being harmed has no power and the institution in power sees no harm