They definitely should have been aware that it's a significant risk. It can't be predicted with certainty, but it was pretty obvious that there's a good possibility of something kicking off. I occasionally take trips where flights connecting in Dubai would otherwise be a good option, but I won't do it. Partly because I'm the wrong ethnicity (yeah, UAE is buddy-buddy with Israel now... so was Iran before the revolution), but the risk of war breaking out is a big part it.
It's not like this is the first time in recent history that region has been somewhat unsafe for travelers. Or the second time, or third, or fiftieth.