Obviously there are a lot of large privately held companies, many of them owned by billionaires, some of whom are very public assholes. Forbes maintains this US-only list (Twitter is 149th and falling): https://www.forbes.com/lists/largest-private-companies/ But, Twitter notwithstanding, most of these giant companies just quietly go about their business. Some of them become conspiracy theory targets (Koch) due to the flex their owners exhibit on the public sphere. And some of this is clearly incorrect in their table (ie: Cargill is not making $1M in revenue per employee -- they probably used US employee count, but global revenue).

Large private companies should be paying more taxes, imo, but are not strictly the problem. Large public companies are evil almost across the whole spectrum. The large private companies don't typically fire 25% of their staff at Christmas just to massage numbers for the quarterly report.

When you look at small companies though (for example, my company is two people, both owners, no employees), I hope you'll see that we're just trying to make a living :)