I didn't know Tom recomends doing a parasite cleanse with the MC but I tell ya, just on logic alone where many parasite tinctures contain alcohol which the body will treat like a poison when fasting and on parasite protocols that use herb pills (solids) that will interfere with the MCs main working mode of giving the digestive system a rest. It's just not logical. Then you have the recorded experiences of forums like this where some folks have gotten real sick to the point of passing out from more toxins being released from die off than the system can handle (herxheimer reaction). Some folks that are toxic can sucumb to herxheimer reaction on the MC alone so it just makes it all an unecesary "risk" when the parasite cleanse and the BPs can be done at any other time and the MC can work it's mojo by itself so one gets the best and most benefefits from each separate protocol without putting themselves at risk of getting ill.
The Clapp thing is the really scary one where he actualy mixes the MC with the PBs and does not talk at all about the imperative need to drink lots and lots of water. I would say he was lucky in both that his issues where probably more related to toxemia from the GI tract and that he didn't have a major blockage from not drinking lots of water as it is always a crucial element when doing the PB shakes protocol
The term "purist' really does not apply as that denotes being dogmatic. It is more about logic, common sense and the shared experiences in forums like this over the last 10 years.