Why don't RSS readers download full text offline?

Question

Android

I tried several readers (gReader, InoReader, FeedMe) that have the offline reading function, but none of them loaded the full text without an Internet connection. Only a short version of the news and an image is loaded, when double-tapping it says "Network error", "Not network", etc.
Why is this happening? Can you write in detail about how to get the feed offline in one of these readers?

Answer 1

As I understand it, offline reading is possible only after you have viewed the news and it has been cached. Well, either in the settings there should be some kind of checkmark. Of course, they cannot download news without the Internet, because there is no Internet.

Answer 2

Because the developers of the rss readers you mentioned decided not to implement the offline reading function.