Wasn't it more Christianity than the Roman empire that destroyed Celtic/Druid culture (noting that from the 4th century on the Roman empire was itself Christian

Wasn't it more Christianity than the Roman empire that destroyed Celtic/Druid culture (noting that from the 4th century on the Roman empire was itself Christian) ? Druidism also disappeared in Ireland which was never invaded by Rome. As far as I know the pre-Christian Roman Empire was very tolerant of foreign religions as long as they reciprocated by respecting the Roman religion. I'm not sure why Druidism would have been unique in that regard. Do you have any references supporting your assertions and explaining why Druidism would have been singled out among other pagan religions for persecution ?