Every symmetric map has an imbalance on it. If it is 4 way rotationally symmetric then the imbalance is the second level. And if there is no second level and you're literally playing in an octagon, the imbalance is the player with the better skill, better connection, better controller, etc. I mean we can sit here and break it down all day and it would just end up being time wasted in a disingenuous argument. The point is excruciatingly simple: if there is something different than what is expected, the mind finds that stimulating. I consider that an objective truth because the brain just works that way. On an asymmetric terrain map, the "asymmetry" could be a symmetric building located somewhere. Players will find that interesting because it is the only symmetric thing on the map - it is order within the chaos; or perhaps it is chaos within the uniformity of terrain. Now what happens if the building is asymmetric? Well...nothing. The imbalance would still exist because you have a building in the midst of terrain. Therefore, the terrain becomes the repetitive pattern that is tuned out and the building becomes the asymmetry. And if there are multiple buildings, the imbalance favors composition and/or whichever gives the player the most advantage in combat, etc. Again, "asymmetry vs symmetry" are simplified terms in this context that are quite frankly misnomers, but I feel like the implication is self-explanatory enough. The brain simply finds asymmetry unusual, but that asymmetry can change based on the context. Whether the individual likes asymmetry is up to them. Some people are intimidated by things that are not uniform, and that's fine. Again, once you acknowledge that a hierarchy exists, the rest is a matter of perspective.
I thought the rules would be pertinent information because they explain why the warning was necessary. The warning just seemed like the fair thing to do under the circumstances.