If they keep Shabbos and Kosher (really keep, with all of the Halachos) I wouldn’t call them Mumrim Lehachis or say that if they touch your wine it’s Stam Yeinam.
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If they touch my non-mevushal wine (not that I have any, serve any or give any as gifts except small bottles that I know a family will just enjoy by themselves, because of all the halachic issues), it is yayin pogum.
Well, many rabbonim would differ. My example of a frum Yid stuck in a con-servative shul is one thing. I’d still be leery of sharing non-mevushal wine with him until we spoke more, but it would come out very quickly that he is not a part of the movement.
Your examples are 2 malcontents who put their own feelings and desires ahead of halacha and/or community rules which have the force of halacha. They are 2 Chavas who now have their husbands and children eating from the eitz bli daas (or 2 Izevels who have their husbands worshipping a’z.)