Doing my best,
“Yes, but the man on the platform will not see the strikes at the same time. This should prove that it is not only movement which can change your perception.”
True, he wouldn’t, but he’d know that the strikes occurred at different distances from him, and, doing the math, he’d still calculate that the strikes occurred simultaneously. Setting up the thought experiment with the two strikes being equidistant from both observers is done for simplicity, but it doesn’t change the fact that in one man’s inertial frame of reference the strikes were simultaneous, and in the other man’s frame of reference they were not.
Also, if the man on the train had super long hands and one was in front of the train and and the other in back, he would feel both strikes at the same time.
No he wouldn’t. Let’s say his nerve signals could go from his hands to his brain at the speed of light, i.e., the signals are moving towards his brain at the same speed as the light from the flashes (in reality they go more than a million times slower). As we saw above, the light/nerve signal from the front of the train arrives to his brain before the light/nerve signal from the back of the train. So he both sees and feels the strikes as non-simultaneous. The truth is, they were non-simultaneous to him. Just as much as they were simultaneous to the guy on the platform.
And even though he sees them at different times, that’s because of the fact that the back light hasn’t hit him, but it’s still there.”
That can only make sense if the speed of light from one flash was slower than the speed of light from the other flash, which is impossible.