There are two issues here. One is that the chair’s reasoning doesn’t include any discussion of considering each case’s particular circumstances. The other is that this creates a necessary condition for criticizing a lawmaker, but we need a sufficient condition.

This is just irrelevant—the chair’s argument has nothing to do with whether or not she’s obligated to ensure that public funds are spent wisely in her department.

We know that the chair has praised this lawmaker for playing a watchdog role regarding the military, so this tells us that she should not criticize him for doing the same thing in a case that involves a colleague in her department. That bridges the gap in the argument.

This doesn’t justify the chair’s refusal on the ground she actually gives, which is that she previously praised this legislator—it just makes up a different ground. Also, the chair is only refusing to sign a specific letter, not refusing to ever pass judgment on officials.

This doesn’t get us any closer to justifying the chair’s conclusion, which is about whether or not she should sign a letter, not about her department’s responsibility to spend money wisely.