Well, where the analogy falls down a bit is that traditional UNIX filesystems have traditionally been installed and maintained by UNIX systems administrators.
My point wasn't to blindly defend everything Dropbox has done. I'm sure they've made mistakes, both in design and implementation. My point was that things like their hack of the accessibility panel are, in my opinion, overblown by the average technical reader.
I think bothering the user with an accessibility panel is tedious "Charlie work" that I'd prefer be avoided. I understand why it works the way it does, and I understand the theoretical risk the OS is trying to mitigate. But I'm already trusting Dropbox with my data. It's silly for the OS to treat them like some unknown piece of malware, it's just that the OS isn't a generally intelligent agent able to make accurate determinations of that sort.
I get all that. It doesn't change the fact that I as the user of my computer just want Dropbox to do whatever it needs to do to work. I'm capable of doing the accessibility dance that most applications require, but not everyone is, and I think it's a reasonable position for Dropbox to take that if users are signing up and downloading our app, then implicitly they trust us to check the accessibility box. Is that an objectively acceptable argument? No, but all I'm arguing is that it's reasonable. It doesn't imply maliciousness that that's the argument that won the day inside Dropbox.