governments started to regulate bitcoin due to its price (chance to get undeclared profit) and due to such "underground" websites + online scams.
What people didnt knew at that time when they purchased and sold illegal things for bitcoin on such websites is that bitcoin is not 100% anonymous. Experts from government institutions can track transactions if the transaction was not "scrambled" by mixers. Mixers are the websites which generates bitcoin addresses to split a transaction into 4 and then those 4 transactions can be splitted again and in the end those last 4 transaction are sending the money to the last and needed address . Nothing unusual here so far but the problem is those 4+4 generated addresses (website' wallets) are volatile, meaning after 24 hours will be deleted from the mixer's database. Its like someone is showing you a suspended bridge to cross to the other mountain but after you reached the 2nd mountain the bridge is blown away. I don't know exactly how mixers are working because i havent used such websites but i can say that the prices to hide transaction's tracks are very high. Meaning only those who are sending big amounts can use it and for example to send 5 BTC to an address ,the mixer will charge you with 0.5 BTC or maybe more. If sender A will send 5 BTC to receiver B with a normal transaction then i think the fees would be much lower than 0.5 BTC but the sender A and receiver B can be tracked by a legal authority. I don't know exactly how but ive read on internet that it is possible.
One of the biggest mixer on the internet has recently shut down and the admin declared that he did it by his own for the sake (image ) of the bitcoin. I doubt that and i think he was constrained by a legal authority but that's my only opinion.
So mixers are encouraging illegal activities and if such websites will be banned then the bitcoin will have a better image.
In the meantime since bitcoin has been launched, a new crypto currency apperead which is known to be 100% anonymous and its called Monero.
If Monero is 100% anonymous and more criminals would be aware of this cryptocurrency then the monero could go up to $ 2000 per 1 unit before gets banned in most countries. I see a shiny future in the Monero price but i don't think this crypto will last forever. Right now governments are distracted by bitcoin which is increasing in popularity