I agree with the prohibition of +1s. The core competency of those who provide this list are moderation and technology, not managing a process through which "involved people [indicate] whether they're for or against it."
That is certainly an excellent function, but it can be offered by anyone who wants to run a system for collecting and displaying those indications. The email list itself is intended to be information rich, and such "approval voting" is not information-rich enough in my view.
It is a shame that the moderated messages require so many steps to retrieve. Is it possible to have the "downloadable version" from
https://lists.ozlabs.org/pipermail/bitcoin-dev-moderation/ for each month contain the text of the moderated emails? They do contain the subjects, so that helps.