It is not exactly «atheism» that is the default position so much as that there is no need to appeal to divine agency in a scientific account of nature. (firstthings.com)
The fact that human agency is explicitly asserted in verse 46 — «since you thrust [the word of God] from you and judge yourselves unworthy of eternal life» — strongly militates against any assumption of divine agency in verse 48 and of an eternal decree of unconditional particular election (Shank, Elect in the Son, 184). (redeeminggod.com)