So you're right that this is a bit arbitrary because the line between the standard lib and the language is blurry, but someone writing Rust is going to expect Vec to work, it doesn't even require an extra "use" to get it.
Perhaps a better core example would be operator overloading (or really any place using traits). When looking at "a + b" in Rust you have to be aware that, depending on the types involved, that could mean anything.
Anyway, I love Rust, it just doesn't have the 1:1 relationship with the assembly output that C basically still has.
I got my account locked on BLU because I stopped seeding when my RAID went down. I was able to recover the data and get back up in about 24 hours but there was literally no recourse other than begging some random mod's reddit account.
Always sad to see a tracker go down, but this place was a shit show.