From the middle of that thread[0] we discover that the original author of the original memo commented on it in 2008[1]. That follow-up is definitely worth reading to better understand the context of the memo.
Not reading the follow-up and still criticising/laughing at the original memo is thoroughly unjust. I've submitted[2] the follow-up as a separate item if people want to comment on it.
[0] https://twitter.com/_space_train/status/1236373295429226496
[1] https://www.reddit.com/r/reddit.com/comments/1xz13/in_1974_x...