“I don’t know, that’s just how we’ve always done it.”

In my experience there often is a reason for it, it's just that the person who knew the reason for it left the company and it was never properly documented, so now it's just cargo-cult-policy without any understanding behind it. So you're right, there's no way to figure out why it's done that way or if it should continue to be done that way without thorough reexamination and a pretty analytical approach, and when those reasons are old they can certainly turn out to be badly outdated, but I'd also caution against just blanket assuming that it probably isn't necessary simply because it's "the way we've always done it" and no one seems to know why. The erosion of institutional knowledge is relentless, but that doesn't mean it was never known or never for a good reason either. It's not braindead to follow a policy you don't understand the reason for, it might be lazy and it might be putting too much trust in the people who made the policies, but it's not always wrong. Sometimes the policies are written in blood, and you not knowing that doesn't mean it's not a good policy.