It isn't. Constructive is when you point out a problem and suggest a better alternative. If you just point out problems (especially by taking a narrow legalistic approach to casual conversation) then you're just being a pedant and undermining their substantive argument (in this case, that finding a way to derail the administration is a matter of urgent necessity). You are of course welcome to disagree with that substantive claim, but if so then it's better to do so openly than under cover of fault-finding, which is regarded by many as concern trolling.