Here is the link I referred to upthread. It’s from the Orthodox Union, which is the major certifying organization.
Well, yeah. There are a zillion-and-one rules that food manufacturers have to follow in order to have their products certified as kosher. Some are more obvious than others, but not following any of them can result in denial of certification, with the resulting loss of sales.
It’s not just whether they are leavened, it’s also how long the liquid is in contact with the flour before they are baked. IIRC it can’t be more than 18 minutes, or the stuff isn’t kosher for Passover. Plus you still need rabbinical supervision.
My local supermarket was also ready for Passover, but I went down to the one that has a big Kosher section. They actually understand their target demographic (I think, not being Jewish). I did make the mistake of going there on Palm Sunday one afternoon and ran into the classic elderly New York Jew stereotype when I went to check out. I was torn between being annoyed and wanting to laugh my ass off.