Religions are not the only things people believe in. Some people believe in lab leak exactly the same way some believe in flat earth. With fierce conviction despite complete lack of evidence with just surface level clues.
> Lab leak (or artificial synthesis) is just a theory that explains origin of virus very well.
It's a hypothesis. Most likely unfalsifiable because I have no idea what could prove it wrong. It doesn't explain a single thing about coronavirus and has no predictive power.
> Dismissing it without investigation would be unscientific.
What is posited without evidence can be dismissed without evidence.
You are of course free to search for evidence even though it was dismissed. And come back if you find any.
Some people looked for evidence over last two year and so far they haven't found anything new or interesting.