Would you have preferred it if parent wrote that sometimes people are nice? I didn't read into parent's statement as much as you did. Sometimes communication is messy.
I have no preference on other's comments. Changing that word doesn't change the implication that some people are good/nice because they did it for free, in the context of a discussion about fees.
Can you describe what other meaning there would be in that statement?
The word nice doesn't have as much a moral implication as the word good, which is why I asked.
As for the original sentence, I didn't think it was saying that some people are good/nice because they did it for free. I thought it was saying that some people dit it for free because they are good. That has no implication on whether a person is good based on whether they do it for free. But even if it did, the logic doesn't fall apart if you do an If A Then B analysis. I see no problem with someone doing something for free being a signal that someone is good, especially because I do not say it's an if and only if situation either.
Expecting everyone else should be generous of their time for your mistake is definitely not good.