Losing billions of dollars in one of the biggest trading stories ever seems fairly consequential and will likely affect their future behaviour. That combined with the newfound knowledge that the type of trade they made can be picked up on and exploited is also likely to affect their future behaviour (i.e. don't do that again).

These are shame-based punishments, what happens if these people have no shame?

$3B is not shame.

Sure it is, and most of us have enough capacity for shame that it works on us. Do you think Bernie Madoff feels ashamed about the money he lost? People who have no shame are very powerful, which is exactly why we need actual, meaningful punishment for people like this.