Sokal's paper brought up the possibility of a morphogenetic field affecting quantum mechanics, which sounds slightly less rigorous than a Discworld joke

The concept doesn't come from Sokal but from Rupert Sheldrake who used the term in his 1995 book (http://www.co-intelligence.org/P-morphogeneticfields.html).

There are plenty of New Age people who seriously believe that the world works that way.

Can you identify the factors which caused you to give the statements in this article more credibility than you would have given to any random internet source of an unlikely-sounding claim?

Mostly, the fact that I don't know shit about biology, and the writer uses full, grammatical sentences, cites a few references, anticipates possible counterarguments and responds to them, and more generally doesn't show many of the obvious signs of crackpottery.