As you know I am very pro investor and pro-business, but for years I thought the special tax treatment for "carried interest" was wrong.
I do believe in taxing capital gains at favorable rates to attract investment in the US. Unlike wages, when you risk your capital, you can lose it all. When you do, the government says, "to bad". When you make a return, the government says "where is my share". A bit asymmetrical.
But carried interest is a "bonus" paid to investment managers and is unrelated to money they risked. It is more like a "performance bonus" and when I got performance bonuses they were and should be taxed as income.
On this matter, I think Sinema was wrong. Trump had a similar problem when he tried to eliminate the favorable treatment of carried interest in his 2018 tax reform.
It does show the power of Wall Street to influence legislation and that Democrats are as prone to being influenced as Republicans. I think Sinema is afraid she needs a huge war chest to get re-elected given how many progressive Democrats she has pissed off in the last year. But that is still no excuse for bad policy.