I understand your feelings and it's hard to disagree.  But we have ask whether at some point the US Government gave them the OK to go there and teach.  Had the Feds not approved of it, I can't imagine they'd have been teaching there.  

Assuming they needed to get that approval, and did secure it at some point, then the US Government assumes the same responsibility to them as they do to any other citizen caught in a similar predicament.  I don't see any sound legal basis for giving them substandard assistance -- or none at all.

Having said that, standard assistance has never included "go rescue their azzz".  That's an exceptional degree of assistance that no average American in trouble abroad should expect or, generally, receive.