Forgive my ignorance, but it seems that there is more information in the "explicitly inclusive" form than the "implicitly inclusive" one. Doesn't the existence of the inclusive form allow you to explicitly use a non-inclusive form? So in this case

Lehrer being explicitly male and Lehrer:innen being explicitly inclusive?

I appreciate that this seems to be an emotional topic, but if people choose to use language in a new way, would it not be best to not withhold that information from you as a reader? Someone else wrote that it's like using an ad-blocker, but if I were to read an article, I would want to read it in the exact form someone wrote it, no? It's a bit like Americans auto-replacing "fucking" with "f***g" in their browsers to avoid an annoyance, but they lose information in the process.

When was it introduced and why? It seems in the opposite direction of travel from many languages, which have been trying to make more gender neutral options available.

(exception: Chinese didn't really bother with gendered pronouns until about the nineteenth century, due to the need to translate European languages, so some had to be introduced)