Sorry to answer for Herp' (I'm not going to type that fully name!) and he can give you his own good answer, but the once per week thing is based more on the way our week is structured and human schedules than it being the optimal time. It does work well enough though. Ideally I like to feed young snakes of almost all species more than once per week, reducing to around once per month for most adult pythons. Wild hatchling pythons will often eat a lot more than once per week, but will often be eating much smaller meals than we give them. With wild adults it's often the opposite. Having said that, what happens in the wild is absolutely not optimal (this is a common misconception).
The most common 'wrong handling' is when a snake is snappy and the person picks it up and holds it anyway in a misguided attempt to calm it down. Basically, the snake is striking and biting because it believes the human is a predator wanting to kill and eat it. Despite the attempt to scare away the human and/or flee, the human picks up the snake, which the snake of course sees as having been captured (bizarrely, this is not obvious to most keepers!). The snake continues to bite and/or flee until the session is over and the person puts the snake down, which the snake interprets as being successful in scaring the human predator into letting it go, and so it is unintentionally being trained to bite aggressively (some will argue and say snakes are never aggressive towards humans, but those people are clearly unfamiliar with the definition of aggression despite it being explained in every dictionary).
The above description is very generalised and there are plenty of variations, but it's a basic way to see one common example of how snakes are trained to fear humans. There are other ways it happens and of course there are other ways to interact with snakes which makes them learn not to fear humans. Amusingly, the best way to deal with snakes to train them not to fear humans is very similar to exactly what you do if you have no interest in handling snakes (snakes will instinctively see that you are doing something in the shared environment but don't seem to take a particular interest in interacting with the snake, so you clearly aren't a threat, and down the track if there is a physical interaction, it isn't scary because they've learned that you aren't interested in eating/harming them).
Don't overthink it; young pythons generally become good handlers within their first few months of life, and it's only a few problem animals which don't, and those are the ones which will respond badly to 'wrong handling'. Most of the others pretty quickly catch on in spite of handling being done poorly, just not as quickly as they otherwise might.