Anyone saying that has either an extremely limited understanding of, or more likely has never even watched, one game or the other - if not both.
The forward pass alone makes the games utterly different tactically from either code of rugby (indeed, that's why it's there in the first place), and the four downs limit makes football tactically very different from rugby union, but very similar to rugby league. It's likely that anyone saying such a thing is unlikely even to be aware that there are two different codes of rugby.
Anyone who doesn't see the differences other than the body armour might as well watch the brawls in the alley behind the bar after chucking out time. Or WWE :mwink: