Printed letters are less appreciated because it shows less human effort. But the words are still valued if it's clear they came from someone with genuine appreciation.

In this case, the words from the LLM have no genuine appreciation, it's mocking or impersonating that appreciation. Do the people that created the prompt have some genuine appreciation for Rob Pike's work? Not directly, if they did they would have written it themselves.

It's not unlike when the CEO of a multi-national thanks all the employees for their hard work at boosting the company's profits, with a letter you know was sent by secretaries that have no idea who you really are, while the news has stories of your CEO partying on his yacht from a massive bonus, and a number of your coworkers just got laid off.