If you're a customer of one of the ISPs in question (sounds like you are), you could try contacting them and asking the reasoning behind their blocks of these s

If you're a customer of one of the ISPs in question (sounds like you are), you could try contacting them and asking the reasoning behind their blocks of these sites, and the reason for the inconsistencies you point to. If they brush you off, then since you're in NZ you may also find various NZ gaming or technical community forums on which people have similar feelings to discuss this and see if you can get a more satisfactory answer as a group. Also you might write to your MP or the relevant minister about this and the subject of net neutrality in the broader sense.