Even if only 5-10% of people took offense, it's not worth it to speak your mind.
But in real world it is not true, and risk of witch hunt based on lies/misinterpretations substantially increased in last years.
I agree that there shouldn't be, but as life advice this is a bad thought to operate from. If someone doesn't like you or what you've said, there's always a way to put you in a bad light. With discourse that contains a lot of risk, it's probably better to just avoid it.
When public discourse magnifies the risk of your comments, you'll tend to be risk averse also. Once upon a time, your opinion would be spoken almost all the time, and perhaps put in a letter rarely. The effort for anyone to raise hell over a minor quibble would involve spreading the word, and doing so enough to find the rare people with a tendency to join you. Go back decades and that is infinitely less likely.
Now, chances are your comment is in writing or recorded, and even if it isn't, the quibbler can broadcast their version of events to increasingly wider circles in seconds, at no cost and with virtually no effort.
I delete half of the comments I start writing online, thinking "What's the point? At best, one person appreciates it. At worst, thousands want to argue."
"If you give me six lines written by the hand of the most honest of men, I will find something in them which will hang him.", attributed to Cardinal Richelieu.
The Socratic Method is similar. But it differs because it is trying to expose a contradiction in thought about a particular subject through questions. Whereas you can trick others into critical thinking about a subject just by helping them think critically in general, and it can be done without the use of questions.
Your trick a great idea though, thanks for raising it!