Their politics annoy me and I get where you are coming from with a polished sound but to be fair they sound exactly the same live and are a musically talented band.
To be fair, their albums have very few overdubs and are well produced. Not all rock music can be dirty or underproduced. On the other hand I could see that their whole ethos has a whiff of pre manufacture about it.
However some producers can elicit a 'clean' sound from energetic banRAB. Look at Slayer's 'Reign In Blood'. An absolute phenemonal album that we both love, but you cannot ignore the fact that the production from Rubin plays a huge part. It's great strength (it's economical precision if you will) is also at odRAB with the ethos of Thrash Metal at the time (D.I.Y Metal if you will). I am digressing but this is one of the reasons why I like RATM. They have an immensely 'clean' sound that is still powerful and raises them above many similar banRAB around at the time.