1. The audit excuse is a lie. Its been established a long time ago that there is no legal reason to hold back the taxes.
2. He is running for the President of his country not a kindergarten class. So the tactic of holding his breath until he gets what he wants, is completely unacceptable.
3. He was the guy who.championed the "Obama needs to show his birth cirtificate".
1. While it is not against the law to show someone your tax returns when they are pending an audit, there are plenty of good reasons not to do so (the best of those being to avoid exposing the return to the scrutiny of a thousand DNC auditors, rather than just a couple of dozen IRS auditors). Further, even if they were produced, the public couldn't rely upon the returns as accurate until the IRS demanded whatever reassesments they will demand as a consequence of the audit, and those matters were resolved. These are not legal
prohibitions against releasing the returns, but they are
reasons based in law. Any tax lawyer would advise against publicly releasing your returns in these circumstances. This is the distinction that the Clinton campaign consistently fudges with their statements, and the Trump campaign lacks the subtlety to clarify.
2. It isn't Trump who is owed the 33,000 deleted e-mails, it is Congress, and therefore the American people. She was required to produce them to Congress by law (subpoena). The only reason the person who deleted them (and the person who directed him to do so) is not in prison is that the DOJ of the Obama administration, on the recommendation of the FBI, gave immunity to the Clinton minion who deleted them. It's beginning to look like the reason that happened is that Obama himself knew of the private server and did nothing about it (disclosed via the WikiLeaks Podesta e-mails). The only way this investigation into contempt of Congress will not go forward after the election is if the Democrats can capture the House.
3. Proof of natural born citizenship is one of only two legal requirements to run for President and has been in place since the inception of the constitution. Production of your tax return is not required to run for President (financial disclosure is, and Trump completed that), and is a rather recent tradition amongst Presidential candidates.