I think people are just arguing that this is a terrible practice. Instead of having a clogged up taskbar, you have a clogged up tray. In hindsight, Microsoft should have somehow added a better UI affordance back in the 90s, to disincentives this abuse.

Mac has its own share of applications going against the OS convention. There are quite a few third party Mac applications that annoyingly force the process to exit when the user closes the main window. There are Mac apps that are also starting to intercept ⌘Q and not exiting the process or, infuriatingly, making you hold the key down in order to actually exit (I'm looking at you, Chrome).

I wish product designers would please just stop thinking their app is uniquely special, second guessing OS conventions.