There are problems with either approach, because an LLM is not really thinking.

Always starting over and trying to get it all into one single prompt can be much more work, with no better results than iteratively building up a context (which could probably be proven to sometimes result in a "better" result that could not have been achieved otherwise).

Just telling it to "forget everything, let's start over" will have significantly different results than actually starting over. Whether that is sufficient, or even better than alternatives, is entirely dependent on the problem and the context it is supposed to "forget". If your response had been "try just telling it to start over, it might work and be a lot easier than actually starting over" you might have gotten a better reception. Calling everyone morons because your response indicates a degree of misunderstanding how an LLM operates is not helpful.