arians would refer to arius, the progenitor of the christian "heresy" that taught that jesus was a human being, something that was popular amongst germans and scythians (the goths were mostly arians, after being converted....i guess they could only accept this christian thing to a point, and couldn't swallow the line on immortality) and condemned by multiple church councils. arius was probably greek in origin, and any similarities to the ethnonym of arya - which existed, historically, in the eastern parts of the iranic speaking regions, most prominently in modern day afghanistan, and as we see today primarily through the nation state of iran, and which hitler rather ignorantly used as the name of his imagined nordic race - is strictly coincidental.

he was essentially calling the christians heretics.

but, i think that exchange is seen as mythical by non-muslim historians.