I think the concept is more like, you may participate (invest) but if you don't, you have no standing to have an opinion. (other than the fact that you didn't invest, which represents your opinion.)
Are you saying that they're saying something stupid? The vast majority of companies are regulated by non-investors; and when companies are regulated by people who are also investors, we think it is a problem rather than a requirement for the regulators to have an opinion.