That’s not okay. They do follow most halachos and care. The only problems are womens issues, and a few other kulahs. Are they really as bad as Zoroastrians in your opinion? Wow. That’s quite sad you feel this way about other Jews that believe in God, learn Chumash and Gemara and are shomer mitzvos.
For the record, the Sadducees (tzedukim) did in fact reject Torah she’be’al pen, and only though Torah she’bichsav had authority.
Durthermore, YCT uses the same halachic process many Orthodox Jews do for 90% of the issues. For that they should be respected. This is a far cry from the reform who saw Halacha as primitive, and ignored it altogether. YCT clearly does not ignore Halacha, otherwise they’d serve pork, be mechalel Shabbos, and reject the Torah as being divinely authored. The fact that they don’t do ANY of those things shows they’re a lot closer to you than you think they are.
Broadly painting many Jews that care about their yiddishkeit and Halacha with the brush of avodah zarah is so offensive. Open orthodoxy will not stop keeping all the mitzvos, because for the most part, they ACTUALLY CARE.