However, the "acceptable use" clauses that OP complains about are not part of these ToST Rather they seem to apply to Mozilla "services", which are related to Firefox accounts (https://www.mozilla.org/en-US/about/legal/terms/services/)
You are right! That's really confusing since the acceptable use clauses themselves talk about Firefox services. Their lawyers need to get their shit together.
However, the "acceptable use" clauses that OP complains about are not part of these ToST Rather they seem to apply to Mozilla "services", which are related to Firefox accounts (https://www.mozilla.org/en-US/about/legal/terms/services/)
Side note: strangely, there is no link to https://www.mozilla.org/en-US/about/legal/acceptable-use/ on the main legal site (https://www.mozilla.org/en-US/about/legal).