Because almost everything is risk mitigation or reduction, not elimination.
In particular, in the US, the legal apparatus has been gamified to the point that the expectation becomes people will sue if their expected value out of it is positive even if the case is insane on its merits, because it's much more likely someone with enough risk and cost will settle as the cheaper option.
And in that world, there is nothing that completely eliminates the risk of being sued in bad faith - but the more things you put in your mitigation basket, the narrower the error bars are on the risk even if the 99.999th percentile is still the same.
Risk mitigation is about a) lowering the risk and b) lowering the cost in the event you get unlucky.
This doesn't seem to do the first one. It doesn't actually stop you from doing the things you could get in trouble for doing, even though that was ostensibly the original point.
And the second one is where you want to shave off the high side, not the low side. This is why normal insurance is typically a policy large enough to cover whatever plausible amount of damages there could be and then a deductible so you don't have tons of people filing claims for amounts small enough they could reasonably cover themselves instead of paying the insurance company a margin to do it. But this is the opposite of that, they'd cover a little claim you'd have been able to shrug off regardless but not the one where you'd most want coverage.
I believe the specific purpose of that is to appeal to the parts of companies that engage in professional ass covering for the hot potato.
That is, if a well-established company offers you a service explicitly promising no human bones in the soup, when all the other services don't promise that, you can make a reasonable argument that, in the event you were required by circumstances to pick one of the services to use, you have done the best you can in that circumstance, even if human bones ended up in the soup, as long as the company doesn't have a known history of not honoring its commitments.
And in that case, it becomes easier to make an argument to your management chain that you didn't deliberately put in human bones to save on cost, you picked the one that explicitly promised no human bones.
In particular, in the US, the legal apparatus has been gamified to the point that the expectation becomes people will sue if their expected value out of it is positive even if the case is insane on its merits, because it's much more likely someone with enough risk and cost will settle as the cheaper option.
And in that world, there is nothing that completely eliminates the risk of being sued in bad faith - but the more things you put in your mitigation basket, the narrower the error bars are on the risk even if the 99.999th percentile is still the same.