May I remind you about Deuteronomy 12:32: “See that you do all I command you; do not add to it or take away from it.” (ref)
I don’t want to say that you invited the plague with this … but you kinda did 
Revelation 22:18: “If anyone adds anything to them, God will add to that person the plagues[…]”(ref)
So actually god did forbid to change the source code. And who says the plague has to be a dead first born as it can also be a grumpy user… 
All jokes aside.
What I meant with people rattling at the gates is that I never saw it on any list named “Top 10 Problems with KDE” or something like it.
I don’t want to dismiss any edit done in good faith.
During my evening run I took the time to think about what I disliked about the change and boil it down to an abstract description that is as short as possible:
The edit changed a (1) basic and fundamental feature with (2) no indication of the change or it’s effect and (3) no other option but to comply.
(1) IMO there are only very few functions in a file browser that I would call basic or fundamental. Creating folders is definitely one of them. Moving and deleting folder/files would be other ones. Renaming a folder/file would probably come in fourth, but it’s not used as often as the first three. If you change the behaviour of such a basic feature, you have to be very careful just by the fact of the feature being at the very base of user interaction. I’m not saying that it is forbidden to make changes to it, but that even small changes can have a large impact for the entire user base as it’s not just about creating the folder, but also how this action behaves (eg. Ctrl+Shift+N creates a new folder and auto selects it. I could press ESC or Ctrl+Space but this would double the required user inputs to create more than one folder as you would have to unselect after each new folder).
An example from current development would be uutils/coreutils (GNU coreutils rewritten in Rust). Some people are very skeptical about this as it touches software that is very basic and fundamental to every distribution and the change has the potential to break a lot of other things just by the fact that it touches something at the very base of a running system.
A KDE example: Moving files can now also done with Click+Drag. The default still is Shift+Click+Drag, but the option allows you to configure it to your liking.
(2) There is no indication that there is a new folder inside the existing folder. No animation, no sound, no KClippy pointing or KNavi giving you a hint what happened. This would probably be the same as creating a new folder as hidden folder (“.new folder”) and hiding such files by default. The average user has no indication what happened and wonders why it does not work and the folder does not exist (in their views window) either.
(3) This one is the most important part of all three. As said: It’s not about the change. And it’s not about it being the default. My displeasure is based on that I can not choose, that there is no other way to accept what you did not ask for.
I heavily dislike the default KDE UI bouncy cursor animation when you open a file. A small element, but IMHO this is just a childish feature that does not belong into a professional workspace. But I have absolutely no problem with it existing or it being the default as I can quickly disable it after a websearch.
Other examples:
- I once suggested to change the default behaviour of a hotkey to a different FOSS project and the request got rejected quite quickly as it would break the workflow people are used to. There was no discussion about being better or worse or more or less in line with other projects that have similar functionality. It was strictly about changing the default behaviour. However, having the feature as option in the settings was no problem at all.
- iOS 26 got a new UI (“liquid glass”). For some reason panels have to be transparent now and you do not even have the option to turn it off. On my company phone (where I had to upgrade to iOS 26) I now have a login screen where in some areas I can’t even see the letters on my virtual keyboard or the password typed. The transparent UI (that I already set to it’s most opaque setting) shows white letters on white parts of my background. For some users this is may the blessing they always wanted, for me it’s just a liquid ass in my face that I can not remove. Furthermore the even more bouncy UI makes me feel as if I had stolen the from a child in kindergarten.
- (Another example from the industry) The code for Redstone in Minecraft is known to be buggy and not work as intended. Yet, it is not changed as this functionality is used in many builds by many different people and a change in this system would break their builds.
An idea for a real life scenario that strikes (1), (2) and (3): All the sudden, you now have to turn your key in a mechanical lock into the other direction to lock/unlock a door. Very small change, but it breaks muscle memory that many people have internalised throughout their entire life.
I never wanted to dismiss you work. If you had the impression that I attacked or wanted to attack you personally or your work, I want to apologize for it.
I do not think that you made the change with malicious intent or to directly discomfort users.
I rather re-formulate my comment to a feature request to include the old way as selectable option. My suggestion for places to include such an option are listed below, but I’m also fine with any other solution as long as I have the choice.
- In the main settings app in the same location where single/double click to open is located
- If this setting is too miniscule for such a place: Somewhere in Dolphins own settings.
- Or if it’s actually only about the keybinding: A different entry for the key binding in the settings app where you can choose if the keybinding should create a new folder in the current view or the selected folder.
Lastly I hope my wall of text was not unbearable long