True its not exactly the most trusted source but would it really surprise you that the Thalmor would do that?
true, I could see the Thalmor. being a radical party, would kill babies. But keep in mind that it may be an influential party, but there might be other political parties ruling The Aldmeri dominion that may not practice infant killing. So it may be true but exaggerated.
(And the Thalmor in the second era may not be as extreme as the 4th era ones.)