True or not you informed them I don't see anything alarming about that being a matured man you're responsible for yourself and how you make a living shouldn't be forced out of you to explain just to satisfy others curiosity.
Not sure whether you get my point or not. TBH I don't really care which one is true, but I hope he wants to recheck again his previous posts. Wouldn't it be better if he posted a genuine story?
Sure, being a mature person means you have the responsibility to yourself. It is your income, other people have no right to force you explaining your income. However, when it is your parents, I'm very sure you will explain it if they ask about your income.
When family members get to have a clue about your source of income and how much money you probably be making, they tend to increase their billing on you base on what they believe you're making either monthly or weekly because it's captured that you can afford it. So keeping them oblivion saves you to a large extend.
For the parents, I think it is no problem to tell your source of income even if you may not tell the amount of your income exactly. But for other family members, it is no need to tell them about the source of income. The bad impact won't be only about billing, there will be feelings of jealousy among them about the income if our income is higher. Sure, it is better to keep it secretly to avid the possible bad impacts.