Earlier quoted context omitted.
Why wouldn't they be allowed to? Companies acquire smaller companies and competitors all the time, it's called consolidation. One party want to sell, the other wants to buy. As long as the deal doesn't breach any anti-trust laws, it's good to go.
If this type of deal ( vertical consolidation through acquisition of competitors, and then removing those former competitors' content from competing platforms) isn't illegal, antitrust laws need to be adapted so it becomes so. It's impossible to deny it's purely in detriment to the market, competitors, and consumers.
Either there would need to be some revolution with the legal profession, or congress would have to pass some new law.
What the judges realized is that by an more open definition pretty much any company and any merger could be said to be against anti-trust.
So if you want such a law, you need to actually get some exact definition of how every is judged that can be consistently legally applied.