Plainly untrue. The reason they keep distribution minimal is to maximise the chance of keeping the vuln secret. Your business is plainly less valuable than google, than walmart, than godaddy, than BoA. Maybe you're some big cheese with a big reputation to keep, but seeing as you're feeling excluded, I guess these orgs have no more reason to trust you than they have to trust me, or hundreds of thousands of others who want to know. If they let you in, they'd let all the others in, and odds are greatly increased that now your customers are at risk from something one of these others has worked out, and either blabbed about or has themselves a reason to exploit it.
Similarly plainly, by disclosing to 100 major companies, they protect a vast breadth of consumers/customer-businesses of these major companies at a risk of 10,000,000/100 (or even less, given they may have more valuable reputation to keep). Changing that risk to 12,000,000/10,000 is, well, a risk they don't feel is worth taking.
