The blog author was insulted by (1) the person demanding work for free after he turned down doing it for money, and (2) on the demanders schedule.
It's any professionals right to say, "No, thanks." For whatever reason. There's nothing unprofessional about so doing. Your assertion that just because you offered money someone is obligated to take it -- or do anything for that matter -- is the aforementioned entitlement.
Perhaps he/she was on vacation. Or wanted to see his / her kids. Or wasn't in the mood. Or had other clients that were paying less but were in a long term relationship that is more important/valuable than a one day consulting fee. Or didn't feel like dealing with the accounting hassle of taking a one day fee. Or had an employer that isn't a fan of employees moonlighting. Or just wanted to stare at paint on the ceiling. Any of the above are perfectly good reasons to say no thanks, and that's the end of the obligation, full stop.
It's any professionals right to say, "No, thanks." For whatever reason. There's nothing unprofessional about so doing. Your assertion that just because you offered money someone is obligated to take it -- or do anything for that matter -- is the aforementioned entitlement.
Perhaps he/she was on vacation. Or wanted to see his / her kids. Or wasn't in the mood. Or had other clients that were paying less but were in a long term relationship that is more important/valuable than a one day consulting fee. Or didn't feel like dealing with the accounting hassle of taking a one day fee. Or had an employer that isn't a fan of employees moonlighting. Or just wanted to stare at paint on the ceiling. Any of the above are perfectly good reasons to say no thanks, and that's the end of the obligation, full stop.