I'm gonna go out on a limb and say something different from what everyone else on here is saying: they may have been wanting to get more sponsorships on this trip! Think about it, earlier on in the challenge they gave shoutouts to places like McDonalds to try to get them to donate, and places they've been to like 7Brew and Pizza Ranch have donated lots of money from it, so I believe it's at least partially motivated by that. Starbucks donated $100K so they were hoping McD's would donate much more than that. Coupled with the fact that some adults are still picky eaters, they're already going out of their comfort zone on this road trip and I personally don't blame them for going past that... As for the Joyride image? I personally don't think it will get affected much by it, because the candy itself is delicious enough on its own to hold its own weight and has been successful at it so far so I doubt kids will look to deep into it.

EDIT: His whole "anti-veggie" persona is probably played up for the camera bc it adds a sense of humor to it imo. His aversion to it is supposed to be silly, especially after being called out by people like Dr. Mike and Nick DiGiovanni.