People
"Yes, I thought it would be something like seaweed," agreed Rincewind. "They certainly taste like seaweed would taste if anyone was masochistic enough to eat seaweed."
— Terry Pratchett

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
A sly joke about awful food. Something tastes just like seaweed would, but only if anyone were masochistic enough to eat seaweed. The speaker treats seaweed itself as the ultimate unpleasant meal, so the comparison becomes a double insult to the dish.
Context reviewed