Corner stone of American justice is that you are innocent until proven guilty beyond a reasonable doubt.
Those who insist that President Trump show his tax returns obviously live in the ass back wards French system where the accused is guilty until he proves himself innocent.
If there was any tax crime committed by Trump, the IRS would know about it. Since there is no sounds from the IRS, let the cry babies prove that Trump is guilty beyond a reasonable doubt, or shut the Hell up.
Trump has done just about everything in an unconventional way, which led him to the Presidency. The fact that he does not monkey what all other presidents did, show that he is a long awaited American original.
If you are not willing to display publicly about your taxes, give the president the same courtesy.