Warren Buffet showed his tax returns, also under audit, to prove that...
You're a friggin liar. Even if your tax lawyer advises you not to show the return currently under audit you can release all of the other past years that I'm very sure are done being audited by now.
As for why... it's almost certainly not because you're famous you narcissistic jerk. It's because your returns raised red flags with the amount of deductions, changes between years, etc. I'm no fan of the IRS but they're not going to waste time and precious manpower auditing people 'just because' they're famous. 
See here's the thing, Trumpty Dumpty... you want a budget deal with cuts to crucial services for seniors, disabled, kids, single parents, working class poor, etc while giving more tax cuts to the richest who really don't 'need' the extra $$. We need to see YOUR returns to see exactly how and how much YOU and yours will benefit while screwing so many of the rest of us over. 