Learn English – Meaning “scheming for the masses” in song the Thunder

This is a stock phrase, perhaps more often encountered as to be none the worse for it.

To be the worse for something means "to be in a worse situation as a consequence" of it, and this phrase adds the emphatic negative none = "not at all". Your example could be paraphrased as

Professional mathematicians have never suffered any ill consequence from knowing nothing about the Moore-Penrose pseudoinverse.

Song lyrics are often complex, because (like poetry) they try to evoke emotion with layered meanings.

First, let's look at "getting me high, and making me low". To "get high" means to reach a state of euphoria or bliss, often through the use of drugs. Conversely, to be "low" means to be depressed, dejected, or diminished. In context, it means "that blue" is creating both positive and negative emotions.

Blue is ambiguous here. It could refer to her eye color, and he could be so struck by her beauty that he is moved to these emotions. However, it's also worth noting that "blue" is also a common way to refer to sadness, so it's possible he is reacting to her emotions. He could also be referring to his own emotions in reaction to her eyes.

As I said, ambiguous.