More central would be - as you mention - the falsity of the religious / divine reason context of "guilt." I don't think Epicurus would embrace something he knew to be false regardless of its alleged practical benefits.
Agreed but with that said do you think a "feeling of guilt/disgust/shame" is something an Epicurean can hold as a genuine reason for virtuous activity or is it inheritantly reliant on a fallacy of "divine reason" or "fufilling our function", the same as how we would never accept claims about fearing offending God's will?
Unfortunately the great fallacy is that I feel disgust is both one of the major reasons people are good (most people are just genuinely disgusted at pedophilia for example, i think even Lucretius makes this point about children being one of the biggest reasons for law) but also it's also recognize it's of the biggest reasons (maybe the biggest reason) for why moral progress often takes so long, disgust or shame at the idea of breaking tradition, race mixing, irreligiousity, or not being "patriotic enough", making it a real double edged sword.