The purpose of this type of interview question is, per my argument, to get an idea of cultural fit and estimation skills. Like any measure it picks up some signal and a lot of noise, e.g. bullshitting skills. The trick is to combine measures such that the noise largely cancels out while preserving the signal.
If this were the only type of interview question used the points you brought up would be a legitimate concern. Given that it was, in my case, married in a much greater proportion with concrete questions I maintain that it generated unique, useful information.
Traders generally have, prior to entering a trade, the opportunity to think through everything thoroughly and ask for help on the bumps. There are also times when the cost of the time for analysis is so great that a gut, if rough, call is needed, e.g. holding hard drive manufacturer equity as news of Bangkok flooding breaks. Being able to ball-park figures, after issuing a disclaimer about the uncertainty of one's estimates, is also a generally useful analytic skill.
It should also be noted that part of recognising the priority of things to be analysed is the degree by which they deviate from expectations - generating many of those expectations is a form of intuitive estimation.
But, as I said, it's mostly to estimate whether this is a person we'd like to spend 10-16 hours a day near. Constant righteous indignation would probably get annoying as fast as serial bullshitting.
I'd say the latter.
It's frustrating to work with people who pretend they know more than they do rather than asking for help.