WolfishMusings: Like “says who” said, if someone b’shitto says I fully keep 612 Mitzvos with all chumros, but there is one Mitzvah I don’t agree with, he is a rasha and apikorus who has forfeited his chelek in Olam Haboah plain and simple.
If someone fails to keep Shabbos because he was never educated and doesn’t know Shabbos, or if someone doesn’t act as halacha requires during Chazaras HaShatz as a result of not being educated on what halacha requires during Chazaras HaShatz, they are both a tinok shenishba in each of those areas respectively.
As far as the label “frum”, it is just a label. Discard it, as it has no intrinsic value.