In this case the blame lies with Christopher Kendris, Author of Barron's Spanish Grammar (2nd Ed.) who on page 196 of this generally reliable reference states that bizarro(a) intends brave or gallant.
Point is, in spain (go have a look for usages of this word or the word bizarria on the net does in fact infer gallantry and courage.
The word comes from Italian originally but tends to be confused with the english word that is similar in colombia. This is actually really interesting to think about and does give some insight into the development and evoloution of the language over time, based on the immediate influences.