Refutation:
(1) MahAnArAyaNa upaniSad says:
puruSasya vidhma sahasrAkshasya mahAdevasya DheemaHi tannO rudraH prachOdayAt
tat puruSAya vidhmahe, mahAdevAya DheemaHi, tannO rudraH prachOdayAt
It also says tat pruSa to so many other deities like vakra-tundA (danti- GaneshA), chakra-tundA (nandi), mahAsenA (SanmukhA), including suvarNa-pakshi GarudA.
There is no point to adding exclusivity of puruSa to Vishnu alone
(2) Shree sUktam, which is also a Rg vedic composition on Shree or Lakshmi, does not make even a passing reference to Vishnu as her consort.
(3) There is no mention of even the word “viSnu” in puruSa-sUktam, if at all it makes a mention of anyone it makes a reference to “prajApati” and he is referred to as “kA” or Brahma in Yajur veda.
(4) The connection of viSnu to puruSa-sUktam, by adding uttara-nArayaNam as an appendage is tenuous at best, because the only sentence that is supposed to connect viSnu is “hreescha te lakshmeescha patnyou”. Any person possessing working knowledge Sanskrit will tell that “hree” and “lakshmee” as consorts (meaning modesty and prosperity) are used merely metaphorically as the very next line says “aho rAtre pArshvE”, meaning one who has days and nights as his two sides. If anything, this line (second line) would be more applicable to sUrya Bhagwan than viSnu.
(5) Hree is never referred to viSnu patni in any one of the scriptures.
(6) To equate “Aditya varNam” of puruSa sUktam with mAyOn is a long stretch of imagination.
It is very likely that a “fusion” of vedic Visnu and mAyOn took place in the distant post, but to say that vaishnavism is advocated by vedAs would be incorrect.