Would you care to explain why this should not work and how this behavior is in violation of the language specification?

It is perfectly valid expression. From a security perspective it may be an undesired feature. However Python does neither claim nor promise that eval is secure, see articel https://lwn.net/Articles/574215/ for more information on a failed attempt to sandbox Python. There is also ast.literal_eval() function, which provides limit evaluation of simple expressions.