The New Orleans legend went viral on Friday after he faked getting struck by lightning as part of a promotion with PointsBet USA ... duping some people into believing he was actually injured -- if not worse.

Lightning Strike and Electric Shock Survivors International -- an organization that has members in 13 countries that helps those impacted by similar accidents -- got wind of Brees' commercial ... and they tell TMZ Sports they're not happy.

"The recent Drew Brees lightning commercial is an inappropriate, disgusting method of promoting gambling or any TV commercial campaign," a statement from LSESSI says.

"This is a deadly injury, and it is disappointing to see the continual ridicule of lightning and electrical injury survivors in comical light in which it is presented for commercial gain and profit."

The org. says it did not find any humor in the ad ... considering many survivors are forever impacted after an accident, and it affects their loved ones as well.

"To poke fun at these folks and make this injury trivial is unacceptable, and what example does it set for our children to learn?"

There's more -- "As a survivor, this is very disturbing, the thoughtlessness on the part of the participants who are trying to profit from tragedy is remarkable. Much progress through hard work and education has been made over the last twenty years to lower the lightning/electrical deaths and risk of injury through education and informed knowledge of the dangers."

The org. believes Brees' ad "just set us back 20 years."

"There are many groups working to educate the public and help survivors, this commercial nullifies all their work and encourages unsafe practices to the general public. And all for gambling ... Lightning Bets? How ignorant can you possibly be?"