So the inclusion of tons of false gods to worship was designed to not give offense to Christians? The inclusion of a tarot deck 5e included to tell the future via the Vistani was designed to give a pro-Christian message? The inclusion of demons and devils, the latter designed to corrupt mortals and take their souls to hell is designed with a pro-Christian message in mind? And heck, if we're talking about ugly language, here you go...
How does that stop something Christians feel so strongly about from being offensive? At the end of the day, you have some people playing characters who are making bargains with devils at the cost of souls.
As mentioned above, the core books in 1e and 2e don't seem to force polytheism. The 1e Deities and Demigods Preface goes out of its way to explain "It is is not intended as a treatment of world religions and the rightness or wrongness of their philosophies. It is a simple of historical or literary details man has recorded for all to see. Do not look for a favoring of good versus evil or neutrality versus everything else." And, in the editors introduction: "The most important thing to remember about this book is that, unlike the other AD&D volumes, everything contained within this book is guidelines, not rules. ... We would not presume to tell a Dungeon Master how to set up his or her campaign's religious system."
A religious person who wants to do the equivalent of what WotC is being asked to do now, seems like they would ask for it to be clear that monotheism and lack of magic can make a fine D&D game and to not use symbols from their real world beliefs as part of the game. They would hopefully be told that's already the case as far as monotheism and lack of magic, and hopefully WotC would go through and not have crosses, or a Eucharist, or things named after Satan, or to be sure that monotheism wasn't portrayed by default as it's worst stereotype. (Christianity is far from the only religion with things like demons, devils, and the underworld).
A religious person asking to have nothing that describes anything magical or from mythology in the base game rules doesn't seem like they're asking for their sensitivities to be respected. It feels like they're asking to be able to force their particular beliefs on everyone else with no options for other beliefs to be given.