ISPs are not legally responsible under under the communications decency act. That doesn't make them completely immune to legal consequences. For example, Section 230 definitely doesn't supercede an NSL.

Invoking it also doesn't let you reclaim a DoD contract you lost, or restore public opinion of your company.

(also, protip for trying to convince anybody of anything: don't start out with an assumption that the person you're talking to is ignorant. Replying with "read up on..." is always insulting)