There's a difference between saying that someone is acting like an ass and that the person is an ass or is stupid. Your comments in this thread have consistently been dismissive and disparaging. That's an asshole thing to do.
Most of your response seems to rely on pedantry rather than trying to come to a shared understanding, which ought to be the purpose of discussion:
Gravitational acceleration is not a force. Weight is.
And what is weight but a mass that is acted upon by gravitational acceleration, specifically Earth's? We're on Earth. Until we're talking about climbing Olympus Mons, there's no purpose in shifting frameworks. Similarly, I distinguished between measures of mass and measures of weight back when I was in college. Using metric mass measurements rather than the imperial pounds gains nothing because we are talking about Earth. I did shift to metric because it's easier to calculate. But saying that we should refer to the mass of the bike in kilos rather than pounds is pedantic.
Most of your points here are not wrong, but they're not relevant. Notice that your response has nothing to do with affirming the points you made earlier? How does your treadmill analogy apply?
But I think our disagreement has nothing to do with physics, it has to do with the actual mechanics of going up stairs versus a stair climber. Let's say the standard staircase step has a rise of 7". I'm sure we agree that going up one step requires raising the entirety of one's weight 7". If going up a stair climber step required raising the entirety of one's weight 7", then I would agree that the machine is substantially similar to the real thing (still some difference in gait, forward motion, etc.). If I understand you correctly, you believe that your entire body mass is raised 7" on the machine (per step) same as it does on actual stairs.
My contention is that this is not the case. Your upper body will move, but not the entire 7". I am not going to try to convince you that this is the case. But you can record someone on a stair climber with a measured background and confirm for yourself. But I think you will agree that if your entire body does not move 7" up (and then 7" down before taking the next step), then you are not using the same amount of energy per step because you are not raising an equal weight the same distance.
If your contention is that you still use the same amount of energy without raising the same weight the same distance, that's simply wrong.