Edited: See the bottom section!
It isn’t challenging the response. It is asking for more information. I accept the answer of “good” and then ask for elucidation. The follow up question (“really good or just sorta’ good?”) is predicated on my acceptance of their response. If I were to continue the questioning beyond the initial request for more detail it would definitely be intrusive, especially coming from an arbitrary stranger.
If you were to respond to my follow-up question with anything other than a positive reaction I would not attempt to engage you in any meaningful way beyond that. It hasn’t happened yet, but it is entirely possible that it would!
Edit: I owe you an apology. After a little bit of thought (I posted shortly after you without giving what you said the consideration it deserves) it definitely could be construed as questioning your initial response of “good”, which would be rude. I just had my understanding improved a bit. I hadn’t even considered it that way (even after you spelled it out)!
I am very new to the site, and have, in the short time I have been here, found it to be both a pleasure to navigate and easy to use.
Although I could very well fit under the category of “advanced user”.