No offense to anyone but if it were true that the vaccine was so weakened then why can someone who has received the nasal version spread the virus? And why can't pregnant or postpartum women have it?

Quoted from the CDC
Can people receiving the nasal spray flu vaccine pass the vaccine viruses to others?
Yes, but its rare. (CRPS is supposedly rare too..)

Linkout to CDC: http://www.cdc.gov/flu/about/qa/nasalspray.htm