While Gideon was brave and obedient enough to build an altar, he remains immobile to the Lord’s instructions and continues about his business despite that there is a Baal consecration in his own house.
From the various things I have read, Baal having an altar at Joash’s house was uncommon and meant that Joash was the town’s chieftain and so also a priest of Asherah and Baal. That Gideon needs a dream to see the error of his family’s way shows how much the Baal cult had insinuated itself into the Israelite’s way of life.
Baal, translated as “lord” or “owner” was a Canaanite fertility god. He was the son of El or Dagon and often portrayed with a fish tail. Baal’s consort was Asherah, Ashoreth or sometimes spelt “Astarte” or Ishtar which is more popularity known. She was a “motherly” goddess along with her sister-daughter Anath, as opposed Moloch, the dark cannibalistic side of Baal, and severed as the wetnurse to the gods and associated with Tyre (Lebanon) Sidon (Syria) and Elath (Eilat, Israel).
Raphael Patai, wrote a book that hypothesized that Asherah was actually part of a Hebrew cult of the mother goddess that later morphs into the Shekinah. He had written an earlier book with Robert Graves called the Hebrew Myths: the Book of Genesis. If this is like Graves’ I, Claudius, it is heavy on sensationalism and low on fact. Prof. Graves could spin a good story but most of it was pure fiction so I can’t say. The Times obit is here. I have the Hebrew Goddess, also by Patai, on order through my library, so we’ll see what’s in there at a later date.
The Lord though, through a dream tells Gideon to slaughter a young fat bull belonging to his father Joash, tear down the family altar of Baal, and burn the one of Asherah beside it. After all this is done Gideon is to put up one of the Lord instead.
So Gideon does as the Lord requests but at night like a thief, so no one could see him. Despite his precautions, someone does spot him and rat him out. The mob attacks Joash for allowing it & although Joash knows nothing about the deed, he defends his son’s actions calling upon Baal to defend himself against this infamy.
Joash(to the crowd): Will you fight in place of Baal himself? Can you save him? Anyone daring to say such a thing will be put to death by morning! If Baal is indeed a god, then let him stand up for himself, because his is the altar that has been torn down.
In honour of his deed, Gideon gets the nickname Jerubbaal” (“Let Baal fight against him”), 6:33)