I can assure you that the French take great offense when hapless foreigners garble pronunciation of their words. From some comments I have seen, Maori are not just being precious flowers here. What they object to is people not even making a feeble effort to attempt approximate pronunciation. They rightly perceive that as an insult, as in I hold this language in such contempt that it is not worth making any effort over. Maybe English speakers aren't bothered by this because English is constantly mutilated by people all over the world. It is in no way an endangered language, merely a tortured one.
Never attribute to malice that which is adequately explained by incompetence.
Someone who pronounces Taupo incorrectly isn't trying to insult anyone. They are simply pronouncing it how they have (incorrectly) learned it and therefore feel comfortable pronouncing it.
With any language there is an uncomfortable period while you are learning the pronunciation. You have to work through that valley of death and it's easy to be self-concious. Lose the mind game at that point and it's over. Scolding about pronunciation can easily deter people from trying/learning/caring.
I know my high school (French) French teacher's attitude cost her lots and lots of students. She made French the least popular language at our school. As soon as they could people dropped her class, just to get away from her imperious attitude.