The interests of 'people as a whole' can be used to justify both (compulsory treatment leads to less drug abuse and fewer homeless, compulsory income redistribution leads to more funding for the homeless, respectively), so really what you're saying is that it's okay to throw rich people in prison, but not poor people.
That's what your 'value system' comes down to. Knee-jerk judgments on moral value and rights based on whether a person is successful.
It's very easy to pay taxes. People do it all the time, and it's pretty well documented how to do it. Worst case scenario, you miss something and pay a bit more than you might otherwise have to. I don't know of anyone who's paid taxes properly and been thrown in prison for paying taxes. Hell, if you look like you might be trying to make an honest effort to pay taxes and got it wrong, you can pay them after someone catches you!
It's not very easy not to have a mental illness. It's not something you choose to do. See the difference? One is putting you in prison for something you very easily could've avoided - the other is putting you in prison (because that's what compulsory treatment really is) for being a human being.
Here come the rationalizations for your favored brand of authoritarianism.
Human rights violators always think that their particular authoritarianism is justified.
It wouldn't be so bad if you didn't simultaneously admonish those who support authoritarian laws to force those who are massively abusing drugs to the detriment of themselves and the rest of society into treatment.
You seem to throw all concern for human rights out the window when the object is to take someone's money from them.