I would imagine ASL is so time tested everything is graded in diminutive detail by various "experts", not just players. When you consider its popularity, it becomes even more scrutinized with age.
I agree.
Just recently, we had a highly improbable situation during a game for which we had to look up the rules. I had read the rule in question countless times before in other contexts and wondered why some half sentence was in it because I could not imagine what it might be good for.
When trying to figure out our highly improbable situation, I suddenly realized that this half sentence perfectly addressed it.
Which means that someone who formulated the rule had "been there & done that" years and years ago. For me, this bears witness, that overall the ASL rules, regardless of their enormous complexity, are amazingly consistent and sound (despite the ton of Q&A which are still there). In my experience, many other games which are vastly less complex still have more ambiguity in many of their rules compared to ASL.
But with regard to the opening post and question:
Why are people critizising ASL harshly? I can only guess.
People who critizise ASL will likely compare it to numerous other more or less complicated wargames. Which means that they need to have invested time and effort to understand numerous other wargames.
If these people prefer simpler wargames, then ASL might just not suit them and condemn it for that reason. If people know various other very complicated wargames, then they will have needed to invest a solid amount of time to come to grips with others to develop some sort of proficiency in them. At the same time, it requires a whole damn lot of time to become proficient in ASL. If one is not willing to spent that time, the game might appear frustrating to some compared to those that they can master.
That said:
You will only find out if you like the game if you try for yourself.
Personally, ASL is enough for me with regard to complex wargames. I am still intrigued by World in Flames, but so far I had to admit to myself that I have not enough time to spare to get into it deeply enough to really play it instead of primarily digging through the rules.
von Marwitz