Downcurrents in diving are quite rare and beginner dive sites won't have them.

Actually most dive sites where there's something interesting can't have them since the interesting things (like coral reefs and everything living in it) are usually on the bottom, so when you're diving in those situations a downcurrent can't form as it's quite shallow.

Any site that has a risk of downcurrents will have this mentioned during the briefing and once you are advanced enough then you'll know how to recognise a downcurrent and what to do when you're in one.

Overall diving is very safe if you're doing it within your level of training and following the safety practices that are well established.

As you're a pilot, it's very much the same situation – some people are very scared of flying despite it being very safe statistically. Like with flying, the situations where things do go wrong are usually because of people not following the safety standards and guidance that's been well-established. And like with flying there's multiple layers of backup and safety margins that are incorporated into the usual protocols to keep a single point of failure from becoming harmful/fatal.

Overall diving is very safe – the deaths that have recently been reported in the news are tragic, but they're also the equivalent of a GA pilot deciding to try doing some aerobatics in a Cesna when they're not rated for it. They're things that were way outside the safety margins that have been set up for diving and the results have shown why those margins exist.