Since Apple keeps detailed usage statistics (from the people who opt in) my guess is they know how common such a behavior is and it’s obviously low enough they don’t think this change is a problem.
I agree with some of the other comments I’ve seen that this probably accomplishes what the user is trying to do (ignoring a Wi-Fi network that’s temporarily behaving poorly) and possibly protecting them (forgetting to turn it back on it running up a huge cell bill). I know I’ve heard complaints from people who accidentally did that a number of times.
And also being hassled about location services not working, etc.
You can still actually disable both through the settings up, just not with the quick access.
For everyone else, the new behavior allows users to disconnect from bad Wi-Fi in Control Center while improving their battery life in case they forget to turn Wi-Fi back on.
I still can’t belive this decision. I keep my Bluetooth and Wi-Fi off as much as possible and it’s now difficult to to as a result of this change is ios11. Really bothers me.