Yes, but we're talking about someone who has been vomiting 3+ times per day for three days and is unable to drink water.
The trouble with taking quotes from clinicians is that you don't get the whole story. I'm sure those people had as much bed rest as needed, especially if dehydration is a concern. I'm sure when Chris did his first 25 day fast he wasn't running a marathon either.
Maybe it's obvious but it's better to point out the obvious than have something bad happen.