1. I did not say , he is an imbecile, I said, he isn't very comptent.
... They mean the same thing.
2. Aradin can just leave again, which is pretty likely when he and Zevlor fight each other.
Aye. But Halsin doesn't know that. He doesn't know Aradin will get into an argument because Aradin was being chased by goblins...
3. The goblins can thin themselves out by ... finding the grove? Wasn't that according to you the thing, oh so wise Halsin wanted to prevent?
Yes. But it is an example of an action that we know the goblins will take. Halsin doesn't know specifically that they will find the Grove or that his only time to act will be when they've found the Grove.
Halsin's actions only look stupid in the eyes of people who know all the eventualities from the scenario. But if you consider his position, where things are uncertain, they seem reasonable.
Why is it so important, that Halsin doesn't look incompetent in this case
Because your stance is that Halsin HAS to be incompetent due to this specific scenario. While I'm pointing out that just because it looks incompetent from us, who know all eventualities, it doesn't necessarily make him incompetent.
