Bitcoin is decentralized, what is good for us, users, because nobody can control BTC.
Unfortunately, we can't control who use Bitcoin and for what purpose, what is not ideal, of course.
Just recently I heard in local news that police discover drug dealers.
They paid for drugs with Bitcoin and this was big news in the media.
Such things really doesn't help us much.
Many financial institutions and governments oppose Bitcoin because it's anonymous and anyone can use it, even criminals.
Some people will not accept Bitcoin because of such things.
So, Bitcoin is great thing but also can be used for something very bad, unfortunately.

Fact is that all kinds of currencies and precious metals are being used to finance illegal activities, but still the media and average joe is blaming Bitcoin for this. They somehow don't realize that Bitcoin is nothing different than fiat. It's money. In that regard it shouldn't be weird to see that people use Bitcoin for all kinds of illegal things. Especially when you consider how convenient using Bitcoin is.

Like the real currency has two negative and positive side. Bitcoin also has two sides, positive and negative, it depends on the individual how he is involved and how he uses, if it uses the criminal may be used for their criminal activities, such as drug trafficking, trafficking in women , child pornography.

Thanks to that anonymity it makes the best way to hide every single transactions of illegal trades. It is the best choice for them for it will be harder for the authorities to trace them and they will have time to escape.

That is a mistake, the best way to do a criminal transaction is cash, which is why criminals in the world keep using cash, the second best way is to use fiat since they can use money laundering and convert that dirty money into clean money that they can use.

We cannot do anything about it, that's happening and I think not all is doing it, we should live with it since it is a part of the growth, if it is not happening, it means there is no improvement and no one values the bitcoin... So it should not prevent us or hinder us from doing transaction from day to day with bitcoin... 

Illegal activities are ones that makes the circulation of bitcoin improve, with them the demand has increase and the price as well. So in my opinion, we should thank them because they are giving us money for our investment, and you are right we cannot control them because there is no restriction with bitcoin.

It will not be bitcoin who will be help accountable but the person who are making illegal activities, bitcoin is just a means that we can use in transacting online and we should be even thankful that bitcoin is here, and do not abuse it by using it in illegal activities as though it has a good system you will be trade if authorities work.

things what make a lot of people make bitcoin as their favorite currency to make an illegal transaction are due its anonimity in term you will like invisible when you received or send money you will not have to see a name , address etc that any other currency required. this is the only thing that mostly misused.