Just because lots of modules appear under Test::Exception in the CPANdeps tree (which, incidentally, you should link to as deps.cpantesters.org, not cpandeps.cantrell.org.uk) doesn't mean that they're only required because of Test::Exception.
Each distribution in the dependency tree is listed only once, so if, for example, Module::Build is required for both Test::Exception and Class::MOP, then it will only get listed under whichever 'parent' module I come across first when grovelling over the dependency tree.
