"I'm not an aerospace scientist, or a radio astronomer, (just a civil engineer) but it seems to me that placing a radio telescope on the Moon's farside, would shield the radio telescope from Earth's EM pollution, (similar to light pollution for optical telescopes) and that this would be an advantage. Am I wrong?"

The Moon has no atmosphere. Therefore how many hundreds of feet of rock do you need to block all of Earth's radio pollution?
All you need to do is be behind a mountain in which the Earth is never visable to you & you will be in a location which wouldn't have any Earth radio pollution. The Earth from the Moon, stays in generally the same area of the sky (because it's tidally locked with Earth). Therefore if you are on the Nearside at equator "in the middle" the Earth will always stay "about" directly overhead, go towards either "side" and the Earth "rises" or "sets". Any location in which earth is low on horizon will have radio shadows caused by terrian, if you are in a crater you will not be able to send or recieve radio signals from Earth- unless your relay your signal to higher ground.