There are plenty of valid complains including many touched on in the article but there is also some unvarnished nonsense.
"Pulseaudio is unsuitable for multiuser mode - yes, many people share their PCs (an untested solution can be found here)."
This would lead one to believe that multiple graphical logins playing sound doesn't work in actuality Pulseaudio runs as a process per user and the observed behavior is the same as switching users on a windows machine. When you switch to a users graphical session that users sound comes out of your speakers. Further this allows it to be configured per user and for it to run without super user privileges. The only thing you can't do is say play music as one user and switch to another users desktop and listen to said tunes while hearing your users applications.
In most cases you actually don't want random apps you can't by design effect or shut up playing over your desktop. So this is the right decision in every possibly way.
"No reliable sound system, no reliable unified software audio mixing (implemented in all modern OSes except Linux), many old or/and proprietary applications still open audio output exclusively causing major user problems and headaches."
The last application that I recall that I had an issue with grabbing the sound device directly was a 15 year old version of Skype. Pulseaudio does all of the above and as it is and has been the standard desktop apps are expected to integrate with it and by and large that has been the case for about a decade now. The fact that somewhere out there old broken non compliant apps exist isn't a compelling argument. All popular platforms have a mixture of crappy and useful apps. People generally deal with this by using their favorite search engine to find good applications for their task.
"What if the user decides to switch from Windows to Linux when he/she already has some hardware? When people purchase a Windows PC do they research anything? No, they rightly assume everything will work out of the box right from the get-go."
They "rightly" expect hardware that the manufacturer doesn't want to support on Linux will be reverse engineered by volunteers because they already invested their money in a manufacturer that only supports windows. When the kind of person that could help you out makes 200k at Google it turns out that 50k of their time is not available to protect your $99 investment in your printer.
If you pay $15 a month for hulu + hbo, 10 a month for spotify, $14 a month for netlfix, $150 for cable in the next 5 years you will pay.
$900 for hulu
$600 for spotify
$840 for netflix
$9000 for cable
If you paid for all 4 you bought a halfway OK used car. Perhaps a fraction of that might buy a more polished experience you don't need to piss and moan about.
Ultimately everyone will eventually upgrade their machine. Almost all hardware that a consumer would encounter or consider could also run windows. If you are considering switching to Linux and your current machine consider making Linux a part of your NEXT purchase. If you don't like it you can easily turn around and put Windows on it or hey put both.