"In the following code sample, the containing img and is appropriately labeled by the caption paragraph. In this example the img element can be marked as presentation because the role and the text alternatives are provided by the containing element."
As I read that page, role="presentation" is intended to remove the natural semantics of a tag (e.g. have an <h2> be treated as a <div>), rather than to tell the user that there is nothing relevant to them in the given tag?
Alt is a required attribute of the <img> tag, so requiring it is just basic validation. C code won't compile if you omit the semicolon after statements, either.
Then write your own component that extends and removes the requirement. Until then, web tooling is better off explicitly acknowledging that accessibility is an explicit goal.