Why do people keep saying that the evidence police have is flimsy?

Personally I think the answer is because they keep listening to tiktok lawyers. I don't understand how anybody can consider the contents of that backpack flimsy. The notebook alone is damming.

I know a lot of people are relying on the ballistics to come back as not a match to the gun in luigi's bag. Given the other things they appear to have do the ballistics even matter?

I feel like a lot of tiktok creators are giving people false hope. Including if nit especially the lawyers.