I understand that Jerome also stated that all the world (totem orbem) had found itself Arian. (I can't find the reference). So probably somewhere, someone said Athanasius was against the "orbem."
Here's the reference from Jerome...
Jerome (347-420): After these proceedings the Council [i.e. the Synod of Ariminum] was dissolved. All returned in gladness to their own provinces. For the Emperor and all good men had one and the same aim, that the East and West should be knit together by the bond of fellowship. But wickedness does not long lie hid, and the sore that is healed superficially before the bad humor has been worked off breaks out again. Valens and Ursacius and others associated with them in their wickedness, eminent Christian bishops of course, began to wave their palms, and to say they had not denied that He was a creature, but that He was like other creatures. At that moment the term Usia was abolished: the Nicene Faith stood condemned by acclamation.
The whole world groaned, and was astonished to find itself Arian.
NPNF2: Vol. VI, The Dialogue Against the Luciferians, §19.
Latin text: His ita gestis, concilium solvitur. Laeti omnes ad provincias revertuntur. Idem enim Regi et bonis omnibus curae fuerat, ut Oriens atque Occidens communionis sibi vinculo necterentur. SED DIU SCELERA non latent, et cicatrix male obducta, incocto pure, dirumpitur. Coeperunt postea Valens et Ursacius, caeterique nequitiae eorum socii, egregii videlicet Christi sacerdotes, palmas suas jactitare, dicentes se Filium non creaturam negasse, sed similem caeteris creaturis. Tunc usiae nomen abolitum est: tunc Nicaenae fidei damnatio conclamata est.
Ingemuit totus orbis, et Arianum se esse.
Dialogus Contra Luciferianos, §19, PL 23:171-172.
As for the quote about Athanasius, I strongly suspect that it was a common saying which developed about him, and thus for which there is no official source.
DTK