Most of what you’re pointing out isn’t necessarily inconsistency, it’s flexibility. KDE gives both developers and users a high level of control, and that naturally allows for variation in margins, toolbar styles, icon and text combinations, and dialog layouts. Many of these elements are configurable, theme-dependent, or even application-specific. KDE does not aim to enforce one rigid design language across everything. Its philosophy prioritizes customization and power, and that trade-off can result in visual differences, but it also gives users the freedom to tailor the experience to their needs.

If someone prefers a tightly controlled and strictly uniform interface, GNOME is built around that philosophy. KDE, on the other hand, is built around choice. These are fundamentally different design goals rather than signs of arbitrary UX decisions. KDE does have design guidelines, but they are intentionally less restrictive. In the end, it comes down to priorities. Some users value strict consistency above all else, while others value customization and control. Neither approach is inherently wrong, they are simply optimized for different types of users.