It doesn't really help to know that it's dangerous. I might be overly pessimistic, but from my anecdotal evidence, it is very difficult to get users to move from one messaging platform to another. And once you have gotten all of your close people moved from say Facebook Messenger to Whatsapp (In my example) as it's more recognized than, say, Signal - it would be close to impossible to get everyone to move yet _again_ in the near future in the fear of some security flaws.
Other people just don't care as much...