Did you read the article? They're trying to filter out lower relevance items, so that when you search "coffee maker" and sort by price, you don't get a 2.95 coffee filter instead.
But when I search for coffee maker without sort they show coffee filters. Just sort that list by price and let me figure out how to deal with coffee filters. In my opinion a sort should not change the content of the list.
Because I do not trust them? I've seen them get it wrong -- and once you know that "sort by price" may not, in fact, give you the lowest price, it becomes completely useless.
I would not mind if the filtering was optional; but it is not, so this is one more reason to avoid Amazon.