Well, the religious policies of the seleucids was quite pragmatic, unless they lacked funds, then it was a "common" practice to chose a rich sanctuary (some were left untouch by Alexander the Great and had still a great amount of richness). The other key element was the conquest of Judea by Antiochus III. Before, there were surely jewish communities in seleucid lands as some stayed in Babylonia after the autorisation to return from exile given by Cyrus the great. The relations with jewish after the seleucid conquest was not bad, as the king aknowledged their rights, he even founded a small jewish colony, in cilicia if I remember correctly. It changed under Antiochus IV. As described in the books of the Maccabees, a gymnasium was built in Jerusalem and it was seen as indecent by more orthodox jews. In fact I wonder how the diffusion of elements of hellenic culture would have evolved under the Ptolemies who integrated pretty well the jews of Alexandria. So with Antiochus IV rose some moral discontent of orthodox jews and the promise of the hellenized Menelaus high-priest to give gold from the temple to show his loyalty to seleucid rule, and to ensure the king support against the previous High-Priest Jason who took the citadel to retake his throne (as you can read, both had hellenic names). Antiochus made a campaign in Egypt at the time but had to withdraw due to roman diplomatic intervention, so he wanted to ceased the struggle for the high-priesthood but this ended in the looting of the temple, the massacre of the population and finally the implementation of a policy enforced assimilation with pig sacrifice and forced pork ingestion. This situation is also probably at the origin the redaction of the prophecy of the book of Daniel in order to announce the future fall of the seleucid kingdom. In some way they succeded as the Hashmonean created their own Judeo-Hellenistic kingdom in Judea, at first with semi autonomy and later with full independence from seleucid rule.