The JLS bit that says this (a bit unclearly) is in JLS 4.8:
The type of a constructor (§8.8), instance method (§8.4, §9.4), or non-static field (§8.3) of a raw type C that is not inherited from its superclasses or superinterfaces is the raw type that corresponds to the erasure of its type in the generic declaration corresponding to C.
So, since rawAlpha is a raw type, the type of rawAlpha.intList is the erasure of List<Integer> intList(). That erasure is List intList().
As for why, I don't have a citation handy, but raw types are only really in Java for backwards compatibility. That means they only need to work as well as they did before generics; what you're asking for is for code that works just a little bit better that it used to. It's not unreasonable, but it's not what they decided on. :-)
