I don't know much, but maybe he was being straight forward and honest and he came off as having an alternative motive? If he felt like he was being treated like he was not being honest then I could understand him being offended, just not to that extent.

It does sound like something else is bothering him and this was just a tipping point, but I could be wrong. Either way, you did nothing wrong.

If he wants you as a friend, then he is just as responsible for working things out. Nothing is one sided, at least it shouldn't be.

People are used to most people saying things that are not completely honest to get their way. Half truths, etcetera are the norm. The majority are trained to assume and interpret what others say to form the most logical conclusion. Just my random thoughts.