bitcoin in other country is legit they used bitcoin for paying bills, shopping etc. they used bitcoin for buying anything.
but some other country did not accept bitcoin and no tax so they think its illegal.
It is different for different countries. Some county accept Bitcoin as legal currency and people use it withouthesitation. But some county don't allow it as legal currency. It doesn't depend on the government.
In most countries, bitcoin mining is legal. Of course, there are legal ways to mine bitcoin, which generally means using your own resources, such as electricity and processing power. On the other hand, there are illegal ways to mine bitcoin, such as stealing said resources.
In this case, mining bitcoins is legal, but you’re stealing the resources needed to mine them, which is illegal. So it totally depend on the person who mine bitcoin.