Yeah, they screwed up in that example

...
Not sure how they exactly did their research on that... there are more variables that should be added IMO.
For instance, which maturity did they buy? It should be the closest to earnings, if it's 30 days out... it doesn't really work properly since too far out.
Did they delta hedge to neutral? They should when it starts out ITM.
Usually buying earnings straddles does work, especially when you offset some theta by selling some that expire before earnings...