rd: Meh. I compared it to adultery because that was the first thing that came to mind. I wasn’t making a direct comparison. I’m sorry you took it that way.
But, since according to most of the Gedolim of the last generation, both are Yeihareg V’al Ya’avor, the comparison might not be so asinine. And no one you mention, respectable though some might be, holds even close to a candle to any of the Rabbonim on the list signed against interfaith dialogue. Even the main leaders of “Modern Orthodoxy” (R’ Schachter, R’ Willig, the Rav, R’ Aviner, R’ Melamed, R’ Rimon, and more) are very against interfaith dialogue of any sort.