For that matter, it sounds like the founder or someone who works there is in this thread, but even if you were going to appeal to them, the information you could give them would likely just be the same information that the (linked in the post) signup/product pitch page's application form would ask for.
And fundamentally, why would someone want to work with someone who wasn't proactive in figuring this out? I'm sure as Atlas grows they'll be happy to take your money regardless, but right now they obviously wish to filter out the noise as they likely have a vested interest in starting with the most success-oriented founders.
I can't imagine someone who didn't take the 2 minutes to figure out that they have a non-invite-requiring route, and that that's likely because they don't want to shut the door on anons like yourself asking for an in but don't want their existing members having to recommend people they don't know.