Personally I don't get offended when a friend says no to any of my request be it financial assistance or otherwise neither do I blame them.
I discovered that some of these people that tend not to lend out money to their friends or family actually had a bad experience in the past from lending out money. One bad experience is all it takes for some people to make a decision.
We all have individual differences, some people don't mind going extra miles for their friends and families and even strangers in need of help, while some can't lift a finger for anyone. Sadly that's life.