Learn English – Is it grammatically and semantically correct to use “didn’t much like” as a phrase

It does sound like an affected phrase to me. It's a metaphor that compares the former object with the latter object as being similar. It's meant humorously, I think.

To translate: In the first phrase, her 'real' inner person is actually a fragile thing, prone to breaking easily, much in the same way that fine china breaks easily. In the second phrase, Danielewski treats our vocabulary like Silly Putty, meaning that he molds it very easily into whatever shape he wants. I think it's meant as a compliment.

Reason does not need to be logical (one can argue that reasoning is):

The basis or motive for an action, decision, or conviction; a declaration made to explain or justify action, decision, or conviction; a fact or cause that explains why something exists or has occurred; a premise, usually the minor premise, of an argument. (TFD)

Reason is basically answering the question why. It implies rationality.

Logic is a systematic approach to a problem.

The study of the principles of reasoning, especially of the structure of propositions as distinguished from their content and of method and validity in deductive reasoning; a system of reasoning: Aristotle's logic; a mode of reasoning; the formal, guiding principles of a discipline, school, or science. (TFD)

To me, logic is the way one arrives at an answer.

Pre-Socratic philosophers did not appear to follow any logical principles; reason was descriptive rather than prescriptive, a way to understand how people actually think rather than how they ought to think.

This may be a 'semantic unit' handed down to us by philosophers. However, I don't think it's necessarily tautological, as you seem to imply.