Most people would struggle to finish a meal with half those calories, and rightly so - it's excessive. Strongmen could go over that amount a day when bulking, maybe, and that's about the semi-practical limits of the human body (while maintaining at least some semblance of health).

True, but the topic was "one meal a day of 1500 calories" for a muscular individual, i.e. fasting together with a calorie deficit.