Bitcoin is not legalized in some countries for several reasons, mainly due to concern over financial stability, government control and regulatory issues.
What are the reasons why some government had banned or restricted Bitcoins??
there are many reasons why some countries have not ligalized bitcoin.
On like the country were I came from, though I'm not going to disclose the name of my country for reasons best known to me, and the reason why the government of my country have not legalize bitcoin is because they can't have control over bitcoin, and anything that the government of my country can't have control over they hardly ligalized it, though alot of citizens in my country are using bitcoin for online purchases and for transactions, because our government didn't ban bitcoin nor restrict there citizens from using bitcoin, they only said that any of there citizens that is using bitcoin is at his or her risk.
And secondly the reason why other countries have not ligalized bitcoin is because they see bitcoin as a threat to there own country currency, because the citizens might focus more on using bitcoin for transactions and purchase and abandon there own country currency which can be possible.
Thirdly some countries didn't ligalized bitcoin, because they see it as something that can't help there current situation (eg poverty, unemployment inadequate infrastructure lack of electricity and many more) , so those countries are more focus on things that can bring solutions to their current situation, and not bitcoin.
Lastly some countries are still against bitcoin and they want bitcoin to be ban, so you don't expect such countries to legalize bitcoin.