Well then, serious question - not just passive-aggressive snark - why does this happen?

https://www.theguardian.com/news/2016/nov/23/enormous-pop-up...

And other articles too. People inside the USA, travelling ( sometimes for days) to queue (sometimes for days) for a dentist. Why are there organistations in the US whose purpose for existence is to travel around, providing free dental care to any and all comers? Like a medical mission to a country suffering enormous poverty.