I started noticing the scriptures about idolatry and sex when I noticed that preachers always spoke negatively of sex from those scriptures but never mentioned the idol worship. As I thought about it it seemed to me that the idol worship was the central message of those verses. Seemed to me that once part of the meaning of a verse as ignored that the rest of what is being said about the verse must be twisted in some way.
Well to actually pick that up without the knowledge of what was actually going on is rare. Good job. Few teach on the sexual aspects of the error that was involved in the paganism. It was also riddled with witchcraft which most people overlook as well. Few know exactly what an Asherah Pole was. It is even debated among the scholars.
Isa 57:3 But draw near hither, ye sons of the sorceress, the seed of the adulterer and the harlot.
4 Against whom do ye sport yourselves? against whom make ye a wide mouth, and draw out the tongue? are ye not children of transgression, a seed of falsehood,
5 Enflaming yourselves with idols under every green tree, slaying the children in the valleys under the clifts of the rocks?
6 Among the smooth stones of the stream is thy portion; they, they are thy lot: even to them hast thou poured a drink offering, thou hast offered a meat offering. Should I receive comfort in these?
7 Upon a lofty and high mountain hast thou set thy bed: even thither wentest thou up to offer sacrifice.
8 Behind the doors also and the posts hast thou set up thy remembrance: for thou hast discovered thyself to another than me, and art gone up; thou hast enlarged thy bed, and made thee a covenant with them; thou lovedst their bed where thou sawest it.
9 And thou wentest to the king (Molech) with ointment, and didst increase thy perfumes, and didst
send thy messengers far off, and didst debase thyself even unto hell.
Now this passage is about the Baalim worship on the high place, grove and the valley below which was the valley of Hinnom outside Jerusalem. Molech is often mistranslated as 'king' in many translations. They are spelled the same in the Hebrew but here the Rabbis later mis-vowel pointed it from the original non-pointed text.
The passage had already mentioned killing the children in the valley prior in the passage. BTW Molech is a title, not a name, and means 'shameful king'. It is the vowel points that add the pointing for shameful. It is the same 'shameful king' of Babel (Babylon) and of Tyrus. The sending of his messangers via doing acts of worship is a reference to performing ritual witchcraft by sending spirits to perform actions while it calls this act as debasing thyself unto sheol.