If it wasn't intended to communicate X why say it does?
There are a number of terms which, while descriptive, have derogatory connotations, despite not being intended as an insult in their original contexts: "mentally retarded" is an example. "Abnormal" is another. Also "disabled."
As I said before, menstruation, besides being something that most of the women I know consider unpleasant, has been thrown as insults: "must be that time of the month!" "She must be on the rag." etc. So referring to a
person with even a technical term might not be perceived as all sunshine and rainbows.
Personally, I think a better gender neutral term for people who are likely to need tampons is "female" because it refers to sex, not gender. Or at least it's supposed to. It seems that the term, though accurate and not intended to be offensive, might make some trans-women uncomfortable.
The main problem I personally have with "menstruators" is not that it offends me (but I'm male...) but I consider it an awkward word to say.
Now, I agree with you that the taboos and negativity associated with a body process should go away. But you can't make that happen by rubbing peoples noses in the term. You and I can think it's silly for people to be offended by a particular word in context, but we don't get to dictate that. A major part of communication is to consider not only if your word choice represents your meaning, but also if the people hearing those words derive the same meaning as what you intended. In other words, consider your audience when writing your speech. It's not just intention that's important, but perception.