Maybe that works for software engineering, where it's a good idea to pause a release in case someone uses scripts to send a shitload of bad requests to our API and crashes a server because of our bug or whatever, but I understand that that doesn't work 1:1 with the real world, where it doesn't make sense to not have the aviation industry until we perfect self-flying planes.
By that argument, you will:
* beat your wife
* murder an enemy
* shoot up a school full of children
* commit arson
* jump bail
* evade arrest
* die in a hail of bullets
So, assuming all those eventualities, why shouldn't we just put you to death now?
To spare you the rhetorical exercise, the answer is because we don't punish you for the things you might do, but only punish you for a) the things that you have done, b) that we can prove, c) beyond a reasonable doubt, d) in a court of law, e) before a jury of your peers.
That said, whether or not an activist judge allows a presumptively lawful merger to occur is hardly a hill worth dying on. We have remedies for activist judges through an appeal process. Where an appeals process is not available after the merger, we have remedy for anti-competitive companies through regulatory influence, regulatory agency, rule of law, and a court system to back that up.
By that argument, someone will:
* beat his wife - true
* murder an enemy - true
* shoot up a school full of children - true
* commit arson - true
* jump bail - true
* evade arrest - true
* die in a hail of bullets - true
You see, all these things do happen. The parent is not arguing that because something is possible any one individual will do it. You're arguing a very different thing.