> Why did people doubt this?

Because the university departments are held by a certain type of individuals who want to play down and dismiss anything held sacred and holy by tribes, old cultures, religions, etc., explaining them away with "totems", "magic rituals", etc.

This article is ultimately about support for Jordanes' claim that the Goths originated in Scandinavia and then some new findings that the Goths spread by gene flow, not just cultural assimilation. Jordanes was a Christian writing among a Gothic community that had converted to Christianity, and they had no attachment to whatever was "sacred and holy" to their ancestors centuries before. Consequently, historians expressing scepticism about Jordanes claim were not doing it out of any bone with "sacredness and holiness".

Perhaps before trying to depict an ultimately rather minor controversy among historians as some axe ground against the sacred and the holy, it might be worth actually learning about the topic first?