The amount of money is an arbitrary choice, it's Trumps decision to settle with himself because he's head of government.

Also, you say it's an egregious privacy violation, but every other modern president released their tax returns willingly. Trump is bucking tradition here. As per usual.

There's a difference between releasing your tax returns, being compelled to release your tax returns, and someone leaking your tax returns.

The notion that it's a gentlemanly tradition means nothing. Codify it into law if releasing tax returns is such a big issue. In this case particular, I don't think the leaked tax returns have produced the effect that was desired, so it seems silly that this is what it has resolved to. I wonder if it ever mattered at all, given what we know about Trump nowadays.

Ultimately it's the rich people on the hill pulling all strings, the rest of us are just left to hold the bag.