This is what I do as well. The article says it's "redundant and ugly" but I don't think it's redundant at all--it's unambiguous that "I refute it thus." is a full sentence quote that happens to come at the end of a sentence. It's consistent and simple, as opposed to a special rule that says you can elide the outer `.` if (1) the quote ends in a `.` and (2) the quote is the final element of a sentence.