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.