I believe OP mens abusing market power to prevent competition.

Although if it is or not a monopoly and an abuse of market power is dubious, but it clearly is anti-competitive.

This is similar to Amazon shutting off Google Products from any retailers using its platform. It is anti-competitive, but the jury is out on whether it is abusing market power.

TL;DR: you can try to shut off your competitors from the market, as long as you're not abusing your market power to do so.

PS: The Hacker News definition of monopoly has nothing to do with the economics, policy and antitrust definition of monopoly.