> They could (and must) notify the ones they still have data about.

I agree strongly. For what it's worth, this is absolutely not what I took away from your other comment.

The sentence structure is a strong indicator that this is something other than a question.

This could easily be interpreted as:

"They no longer have an obligation to notify the rest, because they might have deleted some of the accounts...duh"

The commenter's clarification removed the ambiguity, but let's not pretend the original statement was crystal clear. I think the difficulty interpreting the comment is also partially a result of just how passive-aggressive many comment threads have become. After clarification, I understand the original intent. Without that clarification, there are two interpretations.

A different way to say this would be:

> "Are you saying they no longer have an obligation to notify the rest just because some of the accounts might have been deleted?"