The meaning of “antitrust” is very clearly defined. You’re allowed not to like it or to think that laws against it should be struck down, or whatever, but you can’t say it’s something it’s not.
Certainly, when a law that wasn’t applied begins to be applied again, I can see certain mental models taking issue with that. Regardless, the law and its historical application and consequences didn’t change, only a politically driven low enforcement period. That was the anomaly.
If you allow one company to achieve market dominance, it suffocates the ecosystem and stifles evolutionary growth pressures. It's concentrated malinvestment into a local maxima that salts the playing field so thoroughly that escape velocity is unattainable by anyone else.
There are models of this. And historical anecdotes and evidence.