I presume that any long term user of Windows knows that you use neither spacebar nor enter to activate a given radio button in certain contexts, it gets activated simply by moving focus to it.
If I have File Explorer Options, General Tab open, and tab to the Browse folder options area which has two radio buttons, I will get the one currently pressed noted as "Pressed," and if I shift focus to the other, it becomes pressed. If I hit spacebar when focus is on either one, which is already checked by dint of having thrown focus there, and then hit spacebar the screen reader announces, "Pressed," but does not toggle the selection state. Even if I have no screen reader on, and deal strictly with keyboard navigation, this is the behavior. These are controls that are "activated by focus" and nothing else. One hits neither spacebar nor enter to change them.
Now, I'll absolutely agree that if I hit enter when I'm on one of those it activates the OK button, the default button control. But you don't use either spacebar or enter to change the value for the radio button you want in the sections above. You simply gain focus on the one you want in the section you are working with, then tab out to the next section.
I'm talking about controls that actually require the use of either spacebar or enter to activate them, not those that "activate by focus." Apples and oranges, really.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
Journalism 101: If someone says it’s raining and another person says it’s dry, it’s not your job to quote them both. It’s your job to look out the f**king window and find out which is true.
~ Jonathan Foster (attributed)