if it refers to me, "musketeer", then the term layman would be a bit "off", I guess I couldn't call myself a master mason with 40 years of experience.
Of course, it was not directed at you and your answer. It can happen in a forum that an expert happens to respond (as in your case), but the professional background of the expert is usually not verified. Besides, many private homebuilders (i.e. laymen) are active here. Tendentially, answers from laymen are more likely here.
It is simply the case that a layman primarily assesses a property based on practicality and appearance. The expert (inspector), however, looks more at the areas that are rather uninteresting to the layman (basement, roof, moisture, etc.). In this case, the potential buyer stumbled over the steel beam. Now the forum is supposed to guess what it is about and possibly still give a purchasing decision, even though no one can tell if the house fungus might be growing behind the photographer.
Therefore, one can only repeatedly advise to involve a knowledgeable person so that the biggest investment of one's life does not lead to ruin.