We aren’t questioning your logic, just your reading comprehension in this case :) OP was correctly describing the case where both lights are blocked from view.
otikik pointed out a case of multiple light sources where overlapping shadows will be darker (otikik is correct)
fregus says "that's not correct" and argues a true case (shadows from one light source will not be darker) which is a bad argument because it tries to overgeneralize. The case from fregus is for the same light source and they cannot use this to argue otikik is incorrect because otikik's argument explicitly requires multiple light sources.
I point out, responding to fregus, how otikik is correct and how you need to consider multiple sources as well as including examples and physical evidence.
You question my reading comprehension for some reason
@fregus explicitly described a scene with two light sources. Thus the question about your reading comprehension.
They actually reference two light sources TWICE in their comment: ("any two shadows, one from each light", "from light A and in shadow from light B"). Hence the question of reading comprehension.