We know and, or, but are conjunctions. If a conjunction is at the head of a sentence or clause, this clause cannot be used as the subject or object of a sentence. It is wrong to say "And he is young is interesting". Instead, say "the fact that he is young is interesting".
But there is one exception in English, the "Just because ... doesn't mean ..." construct. For example, "Just because it works doesn't mean it works well". The sentence is completely acceptable and makes clear sense. You could rewrite it as "The fact that it works doesn't mean it works well", but that's unnecessary and, in fact, it would sound affected except in formal writing. What about the grammar, though? Can we say that "Just because ..." serves as the subject of the sentence? If you ask AI's, they will say Yes. In other words, a clause serving as a subject cannot begin with "because" but *can* begin with "just because", as long as the predicate is "does not mean". This rule is so restrictive that we may as well say it is made just for this specific sentence structure.
"Just because ... doesn't mean ..." is used in everyday English. It has entered writing, even in non-fiction books. But in seriously formal writing, this construct should be avoided, as experts have suggested. The reason, I suspect, may have to do with its unusual grammar, as said before: a clause introduced by a conjunction cannot serve as the subject (or object) of a sentence, generally speaking.