I'm not familiar with this complexity metric, but I immediately wondered if the results had been normalized with regard to the number of lines of code or module

I'm not familiar with this complexity metric, but I immediately wondered if the results had been normalized with regard to the number of lines of code or modules in each framework (The wikipedia article doesn't say anything about normalization). Django does a lot more stuff than bottle or Flask. So if you just sum up complexity of their modules, it's pretty obvious which one will come out ahead.