...that some otherwise learned people do not know the difference between the words

in·tel·lec·tu·al (ntl-kch-l)
adj.
1.
a. Of or relating to the intellect.
b. Rational rather than emotional.
2. Appealing to or engaging the intellect: an intellectual book; an intellectual problem.
3.
a. Having or showing intellect, especially to a high degree. See Synonyms at intelligent.
b. Given to activities or pursuits that require exercise of the intellect.

-and-

snob (snb)
n.
1. One who tends to patronize, rebuff, or ignore people regarded as social inferiors and imitate, admire, or seek association with people regarded as social superiors.
2. One who affects an offensive air of self-satisfied superiority in matters of taste or intellect.

Now, if the author is making the assertion that all/most/many intellectuals are snobs, then I would respond that the author is engaging in "ideological intolerance".