I tried running a 2nd instance of Roblox simultaneously on macos 15 with another account but this shows up, if my mac can handle it then why can't it just let me do it? If I have two copies of an app like Roblox in separate User/Applications folders, macos moves them to the /Applications/ folder.
Sometimes it won't run apps claiming to be corrupted, so I then have to do sudo xattr -cr /Applications/someapp.app in the terminal and they run perfectly fine. It always nags me if I download apps from anywhere but mac app store. Some of these messages can only be gotten rid of by disabling system integrity protection, but then macos blocks you from running MAS apps due to having "permissive security".
I don't daily drive macOS anymore, I switched to Linux on my M1 mac where I can do whatever the hell I want.
My dislike for MacOS started with this. I had a WordPerfect document, and WordPerfect, but it wouldn't let me open it because it insisted that it wasn't a WordPerfect document. And despite the fact that I could open it in WordPerfect on other computers.
It's always been this "I know better than you, idiot" mentality that drove me away. I went back, briefly, when businesses started letting employees request MacBooks instead of Windows - given those two options, OSX is preferable. Plus, it was Darwin by then, and the important UI - the shell - was essentially POSIX.
I well always resent MacOS having the temerity to think it knew better than me, especially in cases when it was wrong but you just could not force it to do something.