I don't understand why this is news. The soldiers superiors gave them incorrect information about bags. Delta's policy is not new and it isn't Delta's fault that someone idiot told those poor guys they could check four bags free instead of three. What do you expect the ticket and gate agents to do, just change company policy on the fly?
Unfortunately the average person has no idea how a business works, so you'll get a lot of comments like "oh how awful" and such. You'll never get away from that because ignorance is sort of a fundamental condition.