It's her being gobsmacked because Lawrence reports that he and Mike displayed an age- and gender-appropriate reaction to a visual stimulus.
Panel 1: We see Elly paying for movie tickets; it would seem that it's a sci fi film because the other patrons are children and the poster features a guy holding a ray gun.
Panel 2: As other, more responsible parents take their kids inside to see Blaster Man, Elly goes off to watch a piece of abuse porn so as to recover from the stress of listening to children, drinking coffee and passing by a model train display while wondering what to get John.
Panel 3: We see Blaster Man about to rescue an actress (who looks like the 2007 model Liz Patterson) in a swimsuit from a monster too ridiculous for the Power Rangers.
Panel 4: Mike, Lawrence and the local mutant children cheer with glee as the dime-store Cthulhu is vaporized.
Panel 5: Their delight turns to horror as an unknown something is taking place on screen.
Panel 6: Since they're now making puking gestures, it's safe to say that horror has changed to disgust.
Panel 7: Disgust changes back to delight as Blaster Man blasts more aliens.
Panel 8: It would seem that he killed the head alien because the kids are really happy.
Panel 9: AS she picks the kids up after the film, Elly asks them how it was; Mike says "Cool". Lawrence says "Yeah...."
Panel 10: "...There was only one kissing scene." Elly is gobsmacked.
Summary: This is because she's sort of dumb and doesn't realize that small boys don't share her love for kissing, hugging and other violence; they'd much rather see a guy in a jump suit blow away the scum of the Universe in self-righteous complacency. Lynn fails to understand that people have different tastes in another area; that's 'cause, unlike her, I'd rather see Elly in there with the kids so she can not only keep them safe, she can explain what they see.