I think it's part of a more general trend to avoid using the past participle as the adjective. I've lost count of the number of times I've seen a phrase described as 'cliche' rather than 'cliched', or a person being called 'close-minded' rather than 'closed-minded'. There is a distinct difference in meaning between the straight forward adjective (dry, close) and the participial adjective (dried, closed). The latter emphasises the action that brought about the state, whereas the former only describes the present state.
I think it stems from laziness and lack of understanding and is, sadly, becoming more and more prevalent. Though, interestingly, I've noticed it a lot more in America than the UK. So perhaps it's a regional variation? Still doesn't make sense though.