The mere fact that btc deals with huge amounts of money means that it's impossible to think it won't be prone to corruption. It's everywhere even with small communities. The very definition of corruption applies to bitcoin if you think about it. Hopefully it just doesn't bloe out of proportion that will lead to btc's ruin
Bitcoin itself can be used for a variety of purposes. Someone uses it for good, and someone for illegal activities
It depends on the various personality of every person. If the background of the users is really bad and it has a high chance to be used as an illegal activities. But compared with the fiat currency and fiat still become a leader to be used for the illegal activities especially for the money laundering or corruption.