I guess it's similar to arguing against a benevolent dictatorship. And I don't mean that to be snide, I think if I met someone living under a truly benevolent dictator I would have a very hard time explaining to them why I think it's a bad and dangerous form of government.

For one, if you don't like something, you don't get to air your displeasure, find common ground with others who feel the same and then band together to do something about it, say, vote out the people who are the reason for it. Benevolent dictatorships tend to bare their teeth once the spotlight of scrutiny hits them.

The parallels to Amazon's response to unionization efforts are uncanny.

Imagine a $2T company. One day CEO decides that his company should stand for only Republican values, donate them handsomely, buy newspapers for them, start TV channels for them, only offer employment to republican leaning persons, introduce new laws through lobby... All of these is in fact legal. When a company becomes too big, a single person can control its resources towards hurting political system, general public good, tilt opinions and so on. You are then relying on this one person to knowingly or unknowingly not make a bad move. Most often, they will.

EU anti-trust takes harm to competing business into account, but American anti-trust is totally focused on consumer harm, and specifically harm from higher prices.

So unsurprisingly, American tech monopolies are usually middleman-monopolies that offer low (often free) prices while squeezing businesses on the other side. Facebook/Google sells the user as the product, while Amazon is GREAT for low prices, but not so great, and sometimes ruinous for the sellers.