Absolutely true. However, everyone knows who the kids are that got an F on the test anyway. In this structure, they get more help and may be more able to get a C- instead. It is even more so with math since everything builds on previous knowledge unlike something like history.

Stigma isn't all bad. It's a motivating factor. Decades ago, the norm was to post grades on the wall for all to see. We lost a lot of motivation when we got rid of that.