Ah, so you don't like the prospect that Baal doesn't have a goal in mind for all his destruction? Well, not all motivations need specific goals. People do things all the time without rhyme or reason and yet we still have a measure of control over ourselves. One would then think that a demon that is naturally predisposed to destruction (or at the least the personification of it) will do it with out without purpose like a force of nature.
Think of it like Warhammer's Chaos God Khorne. He has no
real goals but killing. Anything that leads to more killing such as scaring/coercing/convincing others into killing and denying others from joining rival idealogies through their deaths all help the
main goal of killing. Baal's ideology is similar - it's just called destruction instead.
It may come off as feeling petty but what's wrong with a demon being petty? Baal has good reason to try and destroy Sanctuary since his Brothers were defeated by humans. Besides, there's also a precedent. The Evils have been fighting Heaven for an eternity only because they are "good" and supposedly diametrically opposed. That seems pretty petty to me (but in keeping with their nature). It's like "What? You guys just can't talk it through and leave each other alone?"
