It sounds like those two were only half-watching the movie since:
- While it's true Steven didn't call the Diamonds, he did seriously consider it.
- The rejuvenator didn't permanently wipe the Gem's memories. It was more like factory resetting a computer while keeping the files instead of a total wipe.
They could've pointed out how most of the poison that was supposed to be potent enough to kill everything on Earth somehow didn't turn Beach City into a lifeless wasteland (yes, it did a lot of damage, but no more than your run-of-the-mill natural disaster) and only caused Greg's arm to become necrotic upon contact. If it were really as dangerous as claimed, a single drop should've been enough to take out a town of that size. I liked the movie and all, but it really pushed the limits of my suspension of disbelief.
Steven's pink skin in the third panel is a nice touch, though. Those two might want to leave now while the theater's still standing.