The idea is that any set of ideas can get frozen, and become more of a problem than a help.
As an example of this tendency in common language, people talk about "abiding by the letter of the law, instead of the spirit of the law" and here is that same concern that people have stopped paying attention to what is important, and are focusing on the most superficial indicators.
(Another example is in the Bruce Lee movie when he is schooling a student and points to the moon - the student looks at his finger and gets chastised for not looking at the moon in all its heavenly glory.)
People who talk about this usually use the word "ideology" as a problem (ie defining "ideology" as frozen ideas), and refer to anything ending with "ism" as an indication that freezing has happened.