You have no idea. Many Master Planned Communities have very restrictive CC&R's (Covenants, Codes & Restrictions) that you must contractually agree to abide to in order to buy a property there. I've seen all kinds of fun rules like only being allowed to paint your house one of the approved seven shades of beige, only using one type of roofing material, only planting trees and shrubs in any publicly facing frontage/backage/sideage from an approved list, maintaining no publicly visible weeds, maintaining a green front lawn year round and even put up a minimum amount of holiday decoration (lights) during December. Little Boxes, indeed[0].
The homeowner's association has a lot of power in the US, so it is inevitable that it will be misused and used incompetently. However only in the most close-minded and controlling of suburbs can you not plant a vegetable garden.
In some areas, tall grass becomes a habitat for snakes, which can be problematic for children.
For most areas, it's aesthetic.
Here in the south-east, a short lawn will have no mosquitoes but a grassy area will have plenty (as in you'll get 20-30 bites in one evening outdoors), so that's a strong motivation.
On the other hand, snakes eating all the rats would be good for children. Rats are reservoirs for many human diseases, but the think on the snakes!! is a common alibi for forcing your neighborg not to having shrubs, roses, grass, climbers, rocks, ponds and everything that would make your own garden look duller by comparison.
HOA's and HOA bylaws are normally mandated and created by the bank doing the construction loan. They do this to protect the value of the property while they hold interest in the remaining lots. The mortgage industry also loves this since in the end they may be stuck with a property if there is a default.
In some places, particularly wealthy places built up after WW2. Some people like it because "muh property values". Just as many hate it because "muh freedom"
[0]https://www.youtube.com/watch?v=VUoXtddNPAM