The word for this is "hypocrisy." Pretending to have virtues, beliefs, or qualities that one does not actually possess. Love their feigning concern or care for others while actually exploiting or taking advantage of them for personal gain. Nothing like the essence of pretending to care while secretly deceiving or harming others.
Absolutely true for "knowing pumpers". The "true believers", well, their obstinate foolishness will be their downfall, not so much deceiving others, although they participate in deceiving others (themselves in partcular) without being aware of it. Park et al. + knowing pumpers on one side, true believers on the other. And its the latter that are always caught holding useless garbage shares in a scam entity.