What do we mean when we say it today?
Basically, being the "laughing-stocks" just means that someone is the butt of a joke. It may have come from a Medieval torturing device, but nowadays, we've dropped the "s" at the end of "stock." Why?
When we say this phrase today, we're usually referring to a stock that you need in cooking, rather than the old punishing tactic. Either way, we're pretty sure you probably don't want to be the laughing stock in any situation.