Well, let me ask, what if Simkanin was right? What if the witholding is a violation of the Constitution? And that "lawful tax collection" isn't so lawful after all? What if? We won't know because the judge decided the case before it was ever presented. Denying motions without even reading them is judicial arrogance. Sustaining objections not even made is judicial malprudence. Preventing the defense from even presenting a case, forget presenting it's case, is judicial abuse. Refusing to answer questions under oath because you know the judge won't bother you about it is arrogance and smacks of buyoffs. The whole thing doesn't pass the smell test. It stinks to high heaven. In a criminal case, the judge decides what the law is and instructs the jury; the jury decides the facts.
If the judge is wrong that withholding is constitutional, the Court of Appeals can reverse the conviction. But juries don't decide constitutional questions.
BTW, the Supreme Court upheld the constitutionality of requiring employers to withhold social security taxes from employees' paychecks back in 1937, by a vote of 8-1. They could reverse themselves, of cours (not that I think that's likely), but the issue is still not one for a jury.
See #127.