That’s because we are desensitized. Rav Moshe wasn’t. He has three or four teshuvos repeating that it is assur, and says about someone who held it was okay that “Perhaps they reasoned that this is not derech chibah and taavah – but l’maaseh this is difficult to rely on.”
And it is totally wrong to write (as above) that Rav Moshe “holds that derech chiba is objective, meaning that there are types of touching that are asur and there are types of touching that are mutar”. Rav Moshe writes that “Furthermore I don’t see any inconsistency at all with that which I permitted a person to travel on a bus because there – there is basically no issue of chibah.”