Subtle heightism that would have no occurred if I was tall

Of course height is a factor in those scenarios.

In the first scenario, you mentioned being on the basketball court. Tall men benefit greatly by meeting the preferred body type for athletics, especially basketball, so when a shorter guy enters "their turf" and becomes "over-involved," it's going to agitate the tall man. They don't want any type of disruptions during one of their ego-fests, and they see it as a threat to their throne when shorter men want to become involved in "traditionally tall" activities.

One of the real eye-openers when I first learned about heightism was realizing that friends of mine had a different worldview about social settings. They seemed to always be fulfilled in social settings, and while I was certainly socially-capable, I would always have to prove myself before people would welcome me into any group. Sometimes though, I was never welcomed into a group, and my friends would be welcomed with open arms. I didn't think much of this for a number of years, but I noticed that "proving myself" became an even more intense task as time went by. I eventually started being more selective about social situations, while my friends still had an insatiable desire to "be seen." I assumed that they just weren't very observant and were just following the herd, but piece-by-piece, I started realizing that they didn't have to go through an intense initiation ritual in every social situation, thus, they were energized by such settings. As a short guy, I'm constantly challenged, ignored, demeaned, or sometimes, at best, I'm merely tolerated. My tall friends weren't subjected to a world that constantly bombards them with cues, body language, tones, and other signals that they are unwelcome, so they tend to see the world as a bit more of a happy goatfuck than it being a place where they have to exhaust a ton of energy just to pass the initial screening process. Usually, in casual settings, people won't be rude to a tall man without being given a reason to do so, but a short man is showered with rudeness, doubt, and diverted attention just for the mere sake of being short.

I don't know man. That's a very specific circumstance so I would have to be there to understand all of the subtleties. They could've just been annoyed that you were asking a lot of questions, but of course, tall men do have more leeway in those instances, and people tend to watch their tone of voice and their level of intensity around tall men. As far as the short guy go who they treated well, you're probably right that he had already been "pre-approved" by the group. Being an average height guy, it's probably better for you to look for examples of tall men receiving social benefits to understand how heightism affects any given situation. They were probably annoyed by your questions, but if you were taller, or at least pre-approved by the group, their response would've been more subdued.