The main reason why the bitcoin is banned in some countries is because governments in some countries that the bitcoin have a disadvantages if they will legalize it. For them, bitcoin has bad effects.
Some government ban bitcoin because they think that bitcoin is a threat to their economic financial stability, because they don't have any control in it. And they think that bitcoin is used in doing illegal activities, such as money laundering and buying drugs.
Recently, Bitcoin was used as a cryptocurrency can helps the investor earn many profit to attract the new investor invest in scam coin.
The owner of these scam coins spread some promises, as x5 x10 x100 after complete crowdsale and list on exchange.
Some scam projects said ICO is simply a part of the road to IPO while the fact is ICO = IPO unverified through blockchain. (Ifan, a fake project said these words to take advantage ICO to scam the investor)
Evem, some projects promised profits every month can up to 50% through lending, lol
Therefore, when the government can not manage the ICO market, they can only ban all things related to cryptocurrency in order to limit the likelihood of similar occurrences.