They're not out to kill you, just out to defend themselves. Corals aren't able to move away from threats, so some of them have developed toxins to avoid being eaten. Zoas/palythoa are toxic, but you're not likely to be harmed by doing routine maintenance. As everyone has said, wash your hands after being in the tank, don't touch zoas unless it's necessary, and if you do touch them avoid touching any mucous membrane or exposing open cuts to the coral. Best practice is to wear gloves when you're working near zoas, and goggles are a must when you're fragging them.
I went to the ER after accidentally squashing a zoanthid -- I definitely felt unwell, with a metallic taste in my mouth and rapid heartbeat, complete inability to focus or concentrate, it was very strange. All I could tell the nurse on the phone was that I felt 'high', but not in a good way -- I wasn't hallucinating, I just felt really dopey.
The docs told me (and poison control said the same thing) that all they do for palytoxin exposure is manage the symptoms, much the same way some snake/scorpion bites are handled -- if you experience difficulty with breathing, or your heart stops, they use machines to get you going again and keep you stable until your body flushes out the toxin. I was essentially fine; I was at the ER for less than 12 hours, they monitored me and gave me loads of fluids and let me go home under my husband's care once the 'stupids' started to wear off.