Not hacking, exactly. Game cheats.

The concern with parsing HTML is largely that it keeps on changing. Web developers that I've known seem unable to resist changing the HTML around seemingly just for fun. Add a <div>, change a <p>, alter a class name, and so forth. I'm not sure what the motivation is. It might just be that there are so MANY ways to skin that cat that web devs always have a new way they want to try.

What's really nice about the HTML you are looking at is that they seem to be unusually clear and convenient. There are IDs on most things, and those IDs clearly follow a consistent, transparent, format.