This is true, When I was starting in this trading, my friend who was started making fortunes will sometimes offer foods and drinks but will never lend. And when I talk to him about it, he shares the ideals and it really strikes me as it really makes sense. The one you said ^^^ is almost the same to what he advised.
And you can't force them to lend you. They don't not only because their money is still on trades but they usually think that they can't make money from you unless it has some interest. Because if they use this in trading there is a chance to multiply it.
So many reasons so hated that even your friends don't that but that is how people becoming too exhausted in making money and they become more greedy. Anyways, that is their money, we have no right to complain but instead, we have to work our own without relying on others help.