Most things that we see as controversial or dangerous when it comes to the CCP aren't even apparent to most CCP members.
Joining the CCP isn't generally a decision to turn a blind eye for personal gain. It is difficult to comprehend just how much China controls the flow of information to its citizens (and the ordinary CCP members).
We must distinguish between CCP leadership and the ordinary members. The average CCP member is no evil person and is unaware of any evil acts being committed.
Now you might wonder why people don't investigate rumors they hear from Western media (even if the sources are banned): - Western media tends to attack Chinese culture and pride, attack ordinary Chinese - The Chinese government refuted the news and any contradicting sources are blocked. - Approval of how the country is run is generally high. Han Chinese and other groups are doing as well as never before. (And they truly don't know that there are people who are not being treated well.)
You can consider it the equivalent of national honor society in high school in the US and various honor societies in college, but with membership dues you must pay. Membership is symbolic and people must attend mandatory propaganda classes which they don't take seriously. Why would they do this? Because this is the way to get into many leadership roles in government.
So CCP membership is driven by capitalist motives.
I personally am friends with quite a few CCP members. I assure you they are critical of the government and have no insight into what the leadership is doing.
CCP membership in itself means little. Really depends on how high up an individual is within the party.