You know - I have thought about it many fact (about this theory of tamed stingrays) and that can be truth.
Mind - how much the amount of alligators attacks on humans increased in the 2000s? Why? Because they are fed by humans. This way they lose fear and respect for humans and want to eat them too!
Animals that can be tamed (like cats/ dogs/ dolphins/stingrays(?!) mostly like humans cause they cannot exist without human help/they receive food from humans.
Many stingrays that live in the open too. When people snorkel they feed them. Thus they are good for people.
But some don't know they can get some food from humans. Like the one that killed Irving. Maybe that's the right explanation? Or maybe not?
?
LM