By pure coincidence, I learnt the origin of this nickname last week.

Stella is brewed in Leuven, Belgium, which is apparantly the wife-beating capital of the world. There is a good chance that this has been completely made up as my friend is very entertaining but frequently wrong.

I'm not a beer drinker so not in a position to judge but my Belgian friends tell me they would rather drink pi$$ than Stella. It amuses them no end that it's sold under the slogan "reassuringly expensive" over here.