There's a lot of coulda, shoulda, woulda here. I'm a frequent traveler for work, and I've encountered probably the majority of things that can go wrong: flight delays causing missed connections, rerouting to other airports, aborted landings, flight crews not showing up, equipment failure, you name it. And I've learned a lot about how to prepare for problems, the most important lesson being, "plan for problems."
When you buy an airplane ticket, it's governed by the so-called "contract of carriage", which outlines what you're
actually getting. You might have a reserved seat on a particular flight with a particular departure time and a particular arrival time, but in truth, the airline is only obliged to get you there. Under certain circumstances, as a passenger you have some additional rights (for instance, if the flight is delayed too long due to mechanical or staffing issues, you may be entitled to meal and/or hotel compensation.) But the contract of carriage contains no assurance that it will get you to your destination on time.
As many others here have noted, the wise course of action is to get
trip insurance and/or fly in the day before. I also concur with those who believe they should have had passports, although I don't think that would have helped them in this particular case. For my own travel purposes, I try to avoid any layovers shorter than one hour (longer during the winter) and I just focus on keeping an even keel. As much as we may want to assign blame for what happened, I've found it's far more important to focus on the next move. If your flight into Ft. Lauderdale is horribly delayed, there's no harm in asking the agent about flights to an alternate airport. I once had a situation that required that I be in San Francisco the next day and due to weather, I had missed the last SFO flight of the day (and because it was weather, they weren't paying for a hotel.) They wanted to put me on a flight that would have had me in SFO mid-afternoon the next day. Not ideal. After a bit of cool-headed investigation, they said they had a flight to Los Angeles yet that evening, and could put me on an early morning LAX-SFO flight which would have me where I needed to be by mid-to-late morning. It wasn't perfect, but it was better than the original scenario.
My final point is this: nobody likes delays or cancellations. They're one of the fastest ways to ruin a gate agent's days because they know they have to deal with a LOT of irate customers. It also means they're grateful when customers don't take their frustrations out on them (the agent who set me up with the LAX-SFO connection, which was not one of their usual connections, also thanked me for being understanding: the person in front of me was not.) Gate agents have more power than a lot of customers realize. They can book you on the next available flight and tell you there's nothing more they can do, too bad so sad, but they can also take an extra few minutes and are sometimes able to work miracles. And although they should always do their utmost for everyone, I've found that I get FAR better results when I'm being polite.