@Murkrow No I totally understand what you mean, and you are absolutely right, but I think this is 2 different things here:
— On one part, you need, as you said, lots of building blocks to be able to make sentences, of course
— But on another part, there are also things that *cannot* be separated in blocks, because then they stop making sense, and they are also important to learn to understand the language

I don’t know your level in French or anything, but maybe the issue here is that the idiom segment should come later, when you know more words to be more comfortable with it?
(Don’t know how duolingo handles it either or how soon idioms come up)