No, the buying drugs part is what's 'wrong,' if you consider breaking the law to be a bad thing.
But you're right to point out that, in sheer usage, Bitcoin really has nothing on the USD when it comes to buying drugs. Still, when you're asking why anyone would consider buying drugs with bitcoin to be wrong, you have to understand that not everyone considers that to be a positive or even entirely neutral act. Most people consider a currency whose primary use case involves breaking the law to be a net negative for society.
But you're right to point out that, in sheer usage, Bitcoin really has nothing on the USD when it comes to buying drugs. Still, when you're asking why anyone would consider buying drugs with bitcoin to be wrong, you have to understand that not everyone considers that to be a positive or even entirely neutral act. Most people consider a currency whose primary use case involves breaking the law to be a net negative for society.