Zoanthids themself are not toxic. However, some types of palythoa, parapalythoa, zoanthus, and other anemones have been found to contain dinoflagelates that produces some types of neurotoxins (such as palytoxin). I wouldn't take too much concern over this however, as many large claims have been made with very very little research. If anyone here is into psychology, then emotional contagion would be a good way of desrcibing the whole palytoxin thing.
Wearing gloves is never a bad idea when propogating corals for the saftey of you and the coral.