In previous years, Bitcoin was known to be involved in many fraudulent activities such as Silk Road, which has been an illegal Darknet market for drugs and weapons. Bitcoin was a big strategy by criminals but luckily, Bitcoin has become more mainstream and criminals were caught. Today, Bitcoin is known for being a reliable digital transactions asset but still some Bitcoin is involved in criminal activities.
Reliable Blockchain companies such as Chainalysis have helped to discover more crimes and make Bitcoin more reliable.
Fiat has been used over the years for different purposes, whether good or bad, yet no one, not even the government, has thought of dumping it for another currency or even stopping its promotion, even with the level of devaluation it is going through. Whether we use Bitcoin for good reasons only or not, haters of Bitcoin will still paint it as bad. You can just tell us not to do business with hackers and scammers, but we would only be deceiving ourselves if we think that criminals are not going to make use of Bitcoin for criminal purposes.
Whether we like it or not, everyone, including criminals, will use Bitcoin the same way they've been using fiat for a long time now. Bitcoin is a currency that is not restricted to anyone; we should get used to that fact. There are some things we cannot change, humans will always be humans. So, bothering about how bitcoin is being used should be the least of our problems now.