Because it's a retroreflective patch. The reflection will be orders of magnitude more intense than a diffuse reflection from a white surface.
We are talking about the height of the black tape. This is more accurately measured here as 1.17m, but you claimed 1.35
https://www.metabunk.org/lake-balat...of-the-earth-if-any.t7780/page-19#post-190631
Meaning your laser is pointing down.
By analyzing the video. Did you not see the images in the post you quoted?
I don't see your point here. What is the green line supposed to be?
How can you comare two imaginary points?
Where is the black tape?