On the "what should be taught in science class" angle, there are many points to this and to rational/thoughtful people they should not be controversial:
1. Maori/indigenous knowledge is a valid source of knowledge.
2. Maori knowledge may or may not have been obtained scientifically (according to some form of acknowledged scientific standards).
3. Maori knowledge (specific items) may or may not be accurate.
4. Maori knowledge is likely to be inferior to current scientific knowledge in nearly all cases where they overlap. Example: as impressive as it was that the Mayans developed astronomy and created a calendar, we don't use their calendar today because our modern calendar is better.
5. Maori knowledge/processes do not currently have a significant place in the scientific community, approach or body of knowledge.
6. Maori knowledge did not contribute to the development of current scientific knowledgebase (this is a guess based on my understanding of other indigenous knowledge, e.g. Mayan astronomy).
All of this should point clearly to Maori knowledge being inappropriate to teach in science class, "on par" with mainstream science. Note, that's what the title and opening post of the thread are about. What happens in history class is more complicated and a very different question.
Note, the thesis of the response letter signed by other scientists starts by addressing this:
Indigenous knowledges - in this case, Mātauranga - are not lesser to other knowledge systems.
This is a stunningly false claim/response, at face value and in the context of the topic (on par withs science). The scientific process has been developed and adopted specifically because it is the best we have. Accepted scientific theories are accepted specifically because they are the best performing. Where they overlap, Maori/Indigenous knowledge is absolutely going to be inferior.
People don't like being told such things about themselves/their heritage, and while they have some freedom to decide for themselves if these things are true, where the rubber meets the road, most do not actually believe them even if they believe they believe them. And I say that in full recognition of the COVID anti-vax/science climate. This situation is an outlier and while the COVID example is big, the number of examples are very limited. There's no equivalent in most disciplines. Nobody throws away their air conditioner and says they have faith in God to make their house cool.