This is a low level StackExchange platform feature and would have to be addressed at the general Meta.SE level. That said, I don't expect it to go far. The design philosophy and community preference of SE as a whole has been that asking, editing and answering should be simple and don't require explanations for anything. You always have the option to explain your reason, but it is not required.
The thought process behind this is fairly simple, if you make edits hard, then it may prevent someone from making a valuable, but minor, contribution if they don't feel it is worth also writing up an explanation. It is better to risk someone making a change for unclear reasons (which can be easily be reverted by the OP or the community if it doesn't seem to be helpful) than it is to risk losing a contribution.
If an edit confuses you, you do know who made it and can ask for clarification as to why the edit was necessary (they may or may not give it, as that is their option, but you are also free to revert it if you don't think it helps.)
Similarly, editing questions in such a way that they make answers that have already been written irrelevant is generally considered an invalid edit and will generally be reverted by a mod or the community unless it was absolutely necessary to keep the question open. There's some leeway on this when it is the OP clarifying the question, though still, in that case a new question is generally preferred, even if not as strictly enforced in that case.
Forcing reasons doesn't really help with anything that community monitoring doesn't already provide or that can't be easily requested or fixed, but it does potentially prevent people from participating, so the vast majority of people oppose this kind of change, even though it has been suggested a number of times over the years. (Similarly, required reasons on down votes, close votes, delete votes, you name it, the same suggestions have been made and they've been declined by the vast majority of the community for the same reasons.)
