The use of "Dogs" implies that it applies to general category of dogs, without intending any specific exceptions.
Of course sentences like that will have exceptions. Dogs have four legs. Except Fido, who was hit by a car, and now gets along fine on only three legs. Etc.
However, to take exception to the truth of the sentence completely ignores the grammar point about reported speech. I can say "The moon is made of green cheese" and you still would have to say "Barb said that the moon was made of green cheese" for the purpose of the exercise. It doesn't matter if I'm right or not!
Retired English Teacher