No. They won't be liable. They'd only be liable if they made a specific claim about their product, and I can't see one.
Simply claiming that a product offers "protection" doesn't specify the
degree of protection it offers. Likewise, "more power to control the outcome" doesn't guarantee control of the outcome.
In fact, if you read very carefully, you'll realize that the product is actually being marketed primarily as a means of controlling feelings of anxiety about rape. This is necessary, because in most of the situations a person is actually likely to be raped they probably won't have thought to put their protective underwear on.
Honestly, the only thing that bothers me (beyond making money off fear, which is never a particularly classy thing to do) is that said page is full of really bad advice and heavily misuses the studies it puts forward. It seems to suggest that "self-defence" or "resistance" means actually fighting or physically overpowering your attacker, which is not true and not how statistical studies of rape outcomes actually measure resistance.
Asita said:
I don't understand how exactly they'd make something like that for a pair of briefs, at least not to any extent that provides more than a short distraction.
Short distractions can be very significant in determining the outcome of that situation, because they might afford an ability to escape or to call for help or just spook an uncommitted attacker. A personal defence alarm works on this principle.
Heck, one piece of anti-rape advice I've heard given to women is to try and urinate. It might sound funny. But anything which is unexpected and distracting can help provide an opportunity to escape.