Dr Ambedkar's
Asoka said, "As I venerate the Buddha, the Enlightened One, there is no need to worship any other deity"
need not be taken too literally Asoka said it in so many words in an edict or such document.
It is just a narration style, communicating the intention of a character behind his actions in the narrative by describing as though he expressed the intention. So looking for an edict or such document with these words or asking for such a document may not be a fruitful exercise.
You say,
"The question of 'the emergence of images and idols in India" apart what can be seen here is an example of falsification of historical record, done purposefully, with political agenda in mind.
"
"What do you think is the agenda ?
To me, it all seems to be simple : 1. Whether the quoted words indicate replacement of older deities with Buddha, the Enlightened one or removal of idols is not clear.
If the qoted words are to be interpreted as indicating removal of idols, then the logic is : Dr Ambedkar was opposed to idol worship. He liked Buddhism and Asoka. He thought his favorites Buddhism and Asoka were also like himself opposed to idol worship.
2. Dr Ambedkar's focus was on how Brahmin influence on State affairs, alleged and theorized by him as the result of belief of queens in Village deities etc., was reduced from the time of Asoka.