You are fetishizing scientists: They are normal persons: some are concerned about the truth. Other about power and that stuff. They are morally not any better (or worse) than politicians, fire-fighters,  businessman, priests, bankers, factory workers, whatever.

But even the ones that are honest and intelligent: they live in a very competitive, closed and ego-centered world. They have to adapt and make concessions. People have kids to feed, and morality and integrity sometimes take the back-row. This with the good ones. Lets not discuss the egocentered ones.