since all food ends up in stomach, it seems both are ok.
the reason i think, gerson adds raw salads is gerson knew mastication is important, if you chew 21 times, each bite, you are bring up gastric juices to your mouth to aide in whole food digestion.
if you blend and strain the juice to drink, then use the pulp as food for a second cup to reblend and you chew your 2nd drink each mouthfull 21 times you would be achieving the same effect.
since most people do not chew pulpy drinks i believe gerson uses whole food to encourage the VERY IMPORTANT
mastication process to bring saliva/gastric jouices into the mouth and food.