Actually, this isn't quite the case anymore. It's true that this practice led to filesystem damage with older computers, and that's because the power button used to cut power directly from the computer's hardware, causing a literal "shutdown". Nowadays, though, pressing the power button will signal your computer to shut-down properly. You can, of course, also set what the power button does manually.
I think what you mean is that using the power button can be inconvenient because it won't give you the option to cancel during the shutdown process (which is unfortunate if you didn't save any files you were working on). The shutdown process typically purges your computer's cache, so anything that wasn't written onto the disk will be gone. This isn't a problem if all open files were saved before pressing the power button, though, and the same cache-purging occurs during manual shutdowns as well.
A power-button shutdown is no less "clean" than a manual shutdown from the system menu. I'd encourage you to do some reading on this topic
here. Unless anotherwindowsuser owns a computer from the 90s or earlier, they should be absolutely fine using this method. If you still consider our post dangerous, you're more than welcome to remove us.
Also - Mike, your gif is depicting a Windows shutdown procedure. anotherwindowsuser specifically requested a method for Linux Ubuntu version 20.04. Shakes head.