There are basic rules for good UI design...
.... which a lot of software ignore. It's not a matter of taste. It's lack of a basic knowledge. And it's not just limited to FOSS software, albeit there it's more visible, especially when relying more on volunteers work. Sometimes because the underlying widget library has issues too, sometimes for the lack of precise guidelines about how to develop an UI. On Windows, more or less Microsoft sets the standards, and most just copy - those who don't or have a good design dept., or are Lotus Notes.
On macOS, it's the same with Apple. It's on Linux you may feel the lack of a "leader" who drives the standard, and competing desktop managers and widgets doesn't help.
I know a lot of good programmers who are totally inept at creating good UIs, and some work with me. You have to keep them away from working on UIs, simply. And let those who have a knack for it develop the UI. Also, delivering a great UI takes a lot of time (especially if a good visual designer is not available) and a true understanding of how users are going to interact with the software.
Then there's the issue when marketing people are involved - they are another category who doesn't understand basic rules. Their main idea is attempting to deceive the user with a "great" visual impact, at the expense of anything else. The need to support touch interaction on a single site maybe shown on small devices led to too large elements for whoever looks at the site on a 30" screen...
On product web sites, it becomes also a way to hide information. The less, the better, the visitor will not be able to compare your product with competitors, it will be stuck into your boastful four large words assertions your product is the greatest of all. And you don't know where to click to find the info you need...
Biting the hand that feeds IT
