That's the thing with ancient wisdom. Over thousands of years, it either stands true and turns into common sense, or is replaced with better modern wisdom.
It's also because it was meant to be read by lords and nobles to teach them the basics of war. A lot of them were EXTREMELY disconnected with reality and didn't even fathom basic shit like "Oh yeah your troops need food. They can't just forage mid war like animals would"
I understand finding these things funny when you are a cool, level-headed person or not in a moment of fight or flee situation, but many of us fall prey to dumb reasoning in emotional situations.
Going slightly off-topic, but I'd wager many people have spent a lot of unnecessary money or gone to jail in the heat of the moment. And many of Sun Tzu's or Lao Tzi's (Tao) advice is like: "stop, breathe, and think it through mofo, stop being an impulsive idiot and paying a high price for it"
Nobody who is at risk of getting in a bar fight is having their life turned around by The Art of War. If you're reasonable enough to take a breath and step back from that Chad about to pound your face in, it wasn't Sun Tzu that did that.
There are a few nuggets that are still only obvious when you actually think about it. Like don't fight with a hill behind you because you might need to retreat, do fight with a forest behind you for the same reason.
Or 'fight with the sun behind you' or 'leave enemy soldiers an obvious escape route' or 'be careful with marshy terrain where logistics will become a nightmare'.
It was even more boring than that. The amount of food you need vs is available plus roads mean your pretty limited in what you can even try to do until engines.
Or that castle sieges were much more boring than made to seem and would last months
Huh, what media are you talking about? Might just be the generes I enjoy but I've never seen anything suggest that castle sieges didn't last ages. Wouldn't that kinda go against the point of a siege?
Maybe it's got to do with a confusion of language. Not every attack on a fortified structure is a siege. Like the battles at Helm's Deep or Minas Tirith in Lord of the Rings could be confused with a siege because they are battles around forts and cities. But the intention was to destroy these places, not make the inhabitants surrender.
Hey stealing enemy supplies works great especially when said enemy is too stupid to poison or burn it. Just ask General Sherman, the march to the sea wouldve been a lot harder if Southern leadership was smarter.