For me, I think it is because bitcoin users are unknown, unless they tell themselves. And because of that, government will find it hard to let bitcoin users pay for their taxes, unless they are honest enough. Aside from honesty, I could not find ways on how to determine how much a person own crypto currencies.
Well, yes. Bitcoin users are unknown, unless they tell themselves. Bitcoins are unknown because Bitcoin is anonymous. It is anonymous because a bitcoin user can tranfer and transport a lot of money in just some clicks. It also cause Money Laundering. Bitcoin is not controlled by the government, so that, bitcoin don't pay taxes in every transactions and it is running in the world with anonymity. That's why bitcoin is not supported in some countries.
Governments can still impose taxes on crypto by their gateways. But what really bothers them are possible money laundering. Bitcoin is already popular in deep web which is of course not cool on governments. Terrorism and countries like North Korea are also possibilities why these countries will never tolerate and as much as possible will try to control this technology.
They can impose all the taxes they want, the thing that really bothers them is they cannot take your bitcoin at will, governments and banks are together in this, that is why governments are fine with banks since they can ask banks to freeze any account and they do it, but when it comes to bitcoin that is impossible and they resent bitcoin because of that.
Most countries don't support it because, for them, Bitcoin is something that is competing with their own government-issued fiat money. And any money that is being invested into Bitcoin is money that is not getting invested in government bonds or that country's stock market. Which government would want that? Additionally, it's hard to track and hard to tax. Most countries would want to completely ban it, but can't do so because it would mean violating individual rights. So all they're going for now is adding more regulations and warning potential investors about the price volatility,
There are countries that have special tax benefits for buying and selling Bitcoin. Countries like Germany, Denmark, Belarus, and Slovenia all have tax exemptions depending on the amounts being traded and for how long the amounts have been owned.
In China, it is illegal for any bank or company to be trading Bitcoins but it is legal for individuals to trade among themselves. Many countries in South America have completely banned it. These are usually countries where the government wants to control all monetary transactions very tightly. One of the countries is Venezuela. Equador has banned the use of Bitcoin and all other cryptocurrencies with a vote in their parliament. They are working on their own national crypto money and don't want Bitcoin competing with it.
I think, right now, the only country that is officially accepting it as a legitimate form of payment is Japan.