They are not being ignored. Better versions of those benchmarks exist in-tree: https://github.com/rust-lang/rust/tree/master/src/test/bench (the shootout-....rs). The only reason they're not on the website is licensing problems (which have recently been resolved) and the fact that the benchmarks game is using the 0.11 release (while the in-tree benchmarks are kept up-to-date with the master branch and so don't necessarily compile with 0.11); this new release represents a good chance to push them up.
Those small benchmarks are not good representations of the rest of the world; they are contrived and limited problems, with some fairly arbitrary rules about which languages/implementations are valid to include, e.g. PyPy is not allowed, and Java gets JIT warm-up time etc.
The site could be renamed to be "The Computer Language Implementation Benchmarks Game", since it's not testing the language speed (best approximated by the fastest known implementation), just certain implementations, some of which are designed with priorities above speed in mind (e.g. cPython).
> Java does not get JIT warm-up time! Please stop making up misinformation!
Oh, sorry! I must've been misremembering something someone told me. (Although, how does `Cold` differ from `Usual` there? It's not clear from the text what the difference is.)
> best approximated by the fastest known implementation
Best not to become so confused: " Measurement is highly specific -- the time taken for this benchmark task, by this toy program, with this programming language implementation, with these options, on this computer, with these workloads."
(Seems like a better way to test would be to allow anything, with three sets of numbers. One for "time from source to as far as you can go without input" (i.e. compilation time, loading the source into RAM, that sort of thing) "time from input to end of first run", one for "time for nth run", with n being high enough that the timing settles. So after any JITters are done, that sort of thing.)
Those small benchmarks are not good representations of the rest of the world; they are contrived and limited problems, with some fairly arbitrary rules about which languages/implementations are valid to include, e.g. PyPy is not allowed, and Java gets JIT warm-up time etc.