Earlier quoted context omitted.
The intention is that the random words are selected from a list of 2000 unique, common words. Choosing a sentence is a different strategy, which is less secure. $ wget -O ⅓Mwords http://norvig.com/ngrams/count_1w.txt $ for i in `seq 10`; awk '/^[a-z]{3,}/ { print $1 }' ⅓Mwords | head -n 2000 | shuf -n 5 | tr '\n' ' ' && echo videos possible disease maintenance chair teen documents than without son research interface…
A random 5 words is hardly simple or easy to remember. The entire selling point of passphrases is exactly that. It's a hard problem that is IMO best solved with hardware secure keeping of secrets and a rate limited pincode.
You use well-known the mnemonic trick demonstrated in the last panel of the comic.