amillion
ok, lets back up a bit here.
Originally the word xenophobia comes from the Greek words xénos, meaning 'the stranger' and 'the guest' and phóbos, meaning 'fear'. Thus, xenophobia stands for 'fear of the stranger', but usually the term is taken to mean 'hatred of strangers'1. Xenophobia can be understood as "an attitudinal orientation of hostility against non-natives in a given population".
Xenophobia and racism often overlap, but are distinct phenomena. Whereas racism usually entails distinction based on physical characteristic differences, such as skin colour, hair type, facial features, etc, xenophobia implies behaviour based on the idea that the other is foreign to or originates from outside the community or nation.
read here
Ok, so if I were to say, 'These fecking frogs should feck of back to fecking France and stop baking poncy macaroons in patisseries, so that our bakers can get back to making good and decent fairy cakes' then that would be xenophobic (but not racist).
Calling someone 'mad as a box of frogs' is not xenophobic because it does not express a hatred, or hostility against a non-native.
It is expressing that the person is being ridiculous, and is as mad as a container full of amphibians.
It cannot be racist, as it has no hatred based on physical characterist differences, such as skin colour, hairtype, facial feathures etc.
To say that it is xenophobic or racist because the person addressed as being as 'mad as a box of frogs' is French, when she has not stated this on the thread is simply ridiculous.
If the person had said that she was French, then it would be rude and xenophobic to call her a 'frog', but in this case we have no reason to believe that both of the posters in question searched her history and discovered this.