More anti Zoroastrian propaganda. It doesn't pass the smell test. Imagine if this was remotely true, the entire Iranian population would collapse in 3 to 5 generations due to lack of any viable offspring.
If it's quoting primary sources from historic Zoroastrian texts from their golden age, then by definition its as anti-Zoroastrian propaganda as early Islamic hadith/Koran commentaries are anti-Islamic propaganda. Now, that article covers the basics, I suspect it does not cover all the nuances of the practice and doesn't hit every angle of it either, and then considering the relative lack of Zoroastrian scholarship and theology after the fall of the Sassanids, obviously can't give much info as to its potential evolution given the different path Zoroastrianism would go in an ATL like this topic discusses (in any PoD where the Persians do better against the Arabs). As I suggested above, Sassanid Zoroastrianism could have as much to do with later Chinese Zoroastrianism as 7th century Islam does the practices of Hui Chinese Muslims in the past few centuries.
The Ancient Persians basically invented the harem, although it wasn't called that at that point.