Yes, MS should ignore people with grandpa eye, I understand your argument. But, that's so discriminating users who doesn't have a good eye sight as you.
Forgetting for a moment that you're simply putting words into my mouth...
If those people have poor eye sight and are not doing anything about it (aka, wearing prescription lenses/contacts), then I don't see why they should be considered a major group of users to target. They could choose to cover every possible type of user, but it's just not necessary and would bloat design requirements. People just wear glasses.
If you can see the text very clearly, as I can, it's just so silly, and even specious. I'd rather it be completely fake (like scribbles) as opposed to a middleground (readable text that means nothing).