Elagabalus was of Arab heritage and he was a priest who worshiped a representation of Baal, the very controversial and very foreign God he wanted to make #1.
The article is a book review, that is not the context I see when I read that condemnation. Maybe the book makes that case, but the review does not.
And, referencing your other post, I don't think the scenario in seventeenth century England is comparable to third century Rome. The Roman pantheon was already on the downswing, allowing a priest of Elagabalus to become emperor. A century later Constantine would make a similar move, leading to the still dominant Christianity. Had Heliogabalus been a competent man the move may have been a huge success.