LOL, You're assuming we had a policy?

As long as it is clear, we are allowed to takeoff, if I remember. Considering microbursts seldom last longer than 15 minutes, I kind of doubt they were persisting for the full hour. Either way the aircraft can handle quite a bit, climbs like a rocket, can also land and takeoff with a 20 knot tailwind, so it has a very wide operating range as far as approach speeds go. Sadly however, it has no windshear detection equipment. See no evil, hear no evil? We were trained to recognize the signs and symptoms, that's about it.

If you were flying as a passenger, how did you know what the tower was issuing?

Of the airlines you mentioned though, I would bet the crews all have considerably more experience operating in Denver than those that declined.