It doesn't matter if the software is designed to be themed. If I want it to be themed, I'll theme it anyway, and if I can't, it means the software and the platform it's running on is garbage, and I'll go find a different one.
Nobody is saying that you must not apply your favourite theme to whatever apps you like on your own computer. Not me, not the linked article.
If themes are so important to you, pick your app based on that criteria. If you think an app is garbage because it doesn’t theme well, fork it and write a better version yourself.
The main point of confusion in this whole thread is whether or not the article states you shouldn't apply themes on your own computer. To some, myself included, it kind of does. Linux distributions are not individual operating systems - they're essentially skins on top of Linux kernel, created bottom-up to offer opinionated choices to users. Picking a distribution is like modifying software on one's own computer, except without duplicating the same work other people would do. In this sense, the article does ask users to not customize software on their own machines.
That is an unfair inference because the author of the post explicitly says otherwise. To the extent he is speaking to you, he is only saying "thar be dragons" and that he will not explicitly support your use of a theme—therefore you should file any theme-induced bugs with the theme author and not with him.
