LED glows on low port is set to 0?
After reading the comments and researching "pull up registers" some more, I have come to understand that my mental image of "pull up" registers was wrong. Fundamentally, when the pull up configuration is used, the switch "press" causes a 0 on the pin. When the switch is open it causes a 1 on the pin.I thought it was the other way around, hence the confusion. 

Thanks for all the help and the hints.