Exclusive content.

Netflix has exclusive content. ABC, NBC, Discovery, ... all have exclusive content.

Why does Amazon buying MGM and getting some exclusive MGM content harm consumers?

Less competitive marketplaces harm consumers. Consolidation means less competition. Amazon is already under antitrust charges and investigations in the EU and US for these types of misdeeds.

There is no marketplace for copyrighted content and there can't really ever be one unless you mandate compulsory licensing. If you want to watch Frozen then you have to buy from Disney or one of their approved vendors. You can't take your business elsewhere and so from a monopoly standpoint it doesn't matter who actually owns it. You might not like that Amazon in particular owns MGM because because it means that their content will likely only be available on Prime but nothing was stopping them from making an exclusive deal prior to the merger.

>Less competitive marketplaces harm consumers.

That's not a law.

There are a lot of examples of more competitive markets harming consumers - the trick is regulating the products and the relationship between producer and consumer.

So literally any acquisition is bad?

See my other comment above.

It doesn't increase the amount of exclusive content, though, does it?

If this is your objection: "It is a bad thing for the consumer because it means more exclusive titles which is gives rise to a false market. It looks like consumers have a choice of platforms with content, but when that content is exclusive the consumer ends up having to pay for all the platforms to see the content they want to see. This in effect means more costs for the consumer and less choice."

Then wouldn't consolidating existing exclusive content mean consumers pay for less platforms?