Mr. Musk has promised to make Twitter a “platform for free speech around the globe.” This vision is more or less the same one now-departed CEO Jack Dorsey championed throughout his tenure, and especially in the platform’s early days. But like its industry peers, Twitter has moved over time toward stricter rules. That isn’t because executives have changed their views, but rather because they have learned some lessons after observing how their products can be abused to manipulate elections, or spread health misinformation, or harass people en masse.

Certainly, moderators sometimes make mistakes, and more transparency surrounding enforcement decisions is in order. But a broader backtracking would be an error. To protect speech at all costs and keep Twitter free of bots and spam, as Mr. Musk has said he would like to do, is almost impossible.

As objectionable as Mr. Musk’s flippant attitude toward the challenges of balancing expression and safety has been his approach to the financial regulations that are supposed to govern his behavior.