One argument in favor of removing it (not saying it’s the reason or that they didn’t have other options) is that ctrl-click and open did not obviously do anything different. That is, whether you ctrl-click and open a signed app or an unsigned app, the command in the menu was just “open”, with no indication that you were overriding a security policy. Then the dialog it popped up wasn’t particularly distinct from the “first time run” dialog. There is an argument to be made that going to the security settings and specifically allowing an app is a more clear expression of intent. Kind of in the same way you probably want to open a file you download from the web, but good security practices means the browser doesn’t open it for you on download, you need to explicitly go do it.

That said there’s no reason they couldn’t have fixed either of those issues instead