Sure, we have a right to defend ourselves but as pointed out, in this case, the terrorists could have been armed a lot better as well than with knives, say I've got my Sir Sauer 220 against 3 who have more firepower, I'd just not forget Orlando and I believe an off-duty officer acting as a security guard exchanged fire with the killer at first. Pretty sad all the way around.
Someone should have been around with bear spray quality pepper spray at the least.