PBA: You are assuming that Halacha=morality and that any claim otherwise is Apikorsus. I think R’ Aharon Lichtenstein disagrees with you on both counts. Read his famous article. I could easily hear the argument that we, as human beings, are meant to outlaw immoral things Mishum “V’asisa HaYashar VeHaTov”.
At the very least that halacha does not equal “immoral,” and that halacha should not “be changed.”
I’ve read some of Rav Lichtenstein’s articles. As can be expected, my mesorah is different in some respects and overlapping in many respects. Regardless, Rav Lichtenstein certainly never wrote that halacha is immoral and should be changed, chas v’shalom.