Taxes are important if a governments need to work so if someone is cheating while paying the taxes then he will be punished with legal actions.In crypto currencies most of the people are not paying taxes and even many governments don't have proper taxes for its usage that is why the governments are trying to ban the usage because it if continues for a while then it will cause economical disaster in that country.
Yes ofcourse, tax is important if we want to see our government function very well. But in recent times our taxes are being leveraged by those corrupt officials. So for us tax payers, it would be unfair if we don't see any improvement in our country even if every assets we have had been taxed.