Abe, these are 2 different things. JD Lee is saying that it does not act as a STRONG acid. But no where is it mentioned that it doesn't increase acidity. That is why the Indian version of books are shit. Writing to their wish. Ethylene glycol does increase acidity of orthoboric acid solution. But it may not increase its acidity so much to be classified as a strong acid (which is a terrible way to classify an acid as it is a relative term). Its always better to look at mechanism.
All you need to know is that ethylene glycol DOES increase acidity of orthoboric acid solution and is commonly used in titrations. The reason of increased acidity is formation of cyclic intermediate, which is formed in this case. It is similar to why ethylene glycol forms better acetals than methanol.
My book version is older, so it is less modified.