When I grew up in Singapore, the locations of all data centers are secret by default to prevent terrorist attacks.
"If bank vaults are so great, why would you not advertise their locations". It's a mystery, is what it is.
"Why would you not tell us how to get to the secret dimension if it's so great?" It's just a dumb question.
Yes, but the more important correlation is between keeping something secret and it being a bad idea (at least for some people). It's like using security through obscurity - it has to be kept secret because it's flawed, whereas a bank vault doesn't need to be in a secret location because it has other means of protecting its contents.
There's so many examples of closed source "security" that is just a clusterfuck. Not that mistakes aren't made with open source, but knowing that other people will likely look at your code tends to make people put a bit more thought into it.
More people can however work on a great plan to attack it, which only has to work once, to be worth it.