Ringo never embarrassed himself singing in THE BEATLES. Think about that.
His vocal turn was a part of the product and it was beloved for being just right. When someone’s vocal is a part of something that great it seems a little much to say he couldn’t sing.
There is a difference between “can’t sing” and the eccentric delivery which sometimes, and very famously, gets paired with great art. Like Bob and Neil for instance. I do get the feeling that some people can’t forgive Dylan for not singing like luther vandross, or Merle haggard, or Tom Jones, whomever, as if that makes a difference. I really don’t want to wait for Luther to write Mr Tambourine Man, any more than I need Bob to sing “well.” These are the given conditions.