I am a bit confused by the Pantry Chant and the reference to Chicken Chop Suey. I didn't think they ate much other than the vegetables and herbs and stuff they could collect around the rock and the Gorg garden. Wonder where they get that stuff.
Well...this is just a theory, but maybe they heard the words "chicken chop suey" from one of Traveling Matt's postcards. (He could have written it down from a menu he saw or something). He might have referred to it as "tough" as in tough to get. Knowing how Matt would behave, he would just wander into a restaurant, see some chicken chop suey in the kitchen or on someone's table. He'd think it would smell good, then try to take some since he saw the Silly Creatures eating it. Sounds like something Matt would do, right? After all, he did (unknowingly) shoplift a whole shopping cart of groceries.
The other foods in the song (stroganoff, macaroni, etc.) could also be mentioned this way via Matt's postcards, but the Fraggles might just like the sound of the words and sing them the way kids would, regardless if they knew the meaning or not.
As for the ice cream, Fraggles may know how to make it. The caves that are cold (even in summertime) is an interesting theory. There could be some unique Ice Cave Gobo discovered, then visits it periodically to bring back ice like those old fashioned ice delivery guys did years ago.
As for "pink ice cream" (from the song) wouldn't be too far fetched. Think about it. What are the ingredients in homemade ice cream? Ice, milk, some kind of fruit and sugar.
Well, considering that Gobo finds a cave where ice grows on the stalagtites, that counts for the ice. This idea can't be too far out there, considering all the other odd things one may find in a cave in Fraggle Rock (an invisible bridge, magical grapes that make you weightless, portals to Outer Space, a spot to teleport back to ancient Fraggle times, a tunnel that shifts back and forth like a railroad switch (Table Rock Cavern), etc.)
Fraggles have access to milk (Red and Wembley spilled it and tried not to cry over it). There may be animals that are milked like cows in Fraggle Rock, but they aren't mentioned. Gobo's still pretty young and still jittery about entering Outer Space in this episode, so I'd rule out the possibility of him raiding Doc's fridge to get milk. Later episodes, yeah, but not here.
As for fruit, the Fraggles definitely know about some kinds of fruit. There's mushmelons (featured in 'Sprocket's Big Adventure') and a lot of references to peaches are in the show: Peach and Pepper Potage (Wembley's favorite dish), peach and garlic pie, there was another peach one, too but I forget what it was.
There is at least knowledge of bananas in Fraggle Rock. How else would Wembley know what was on his shirt he's worn in every single episode?
Then there's sugar. It's easy to picture the Gorgs growing a small patch of sugar cane or other types of Gorgish plants with natural sugars in them. Some may also grow within Fraggle Rock (maybe near where the banana trees are that inspired Wembley's shirt design?)
We can also guess that Sweetwater (found all over the place in Fraggle Rock) can have sugar in it. Remember it from "Gobo's School for Explorers"? The stuff looked like pink lemonade.
Boober and Ma Gorg make a lot of desserts: cookies, pies, cakes...there's got to be a sugar source somewhere.
Also, Wembley's pretty hyper at times. Could be due to a lot of sugar in his tea. We know that Fraggles make tea. Certainly Boober added sugar at some point, since he cooks and all.
We also can't rule out the possibility of Boober wishing for a way to keep things cold, perhaps by using an "ice box" like people used before refrigerators were common. Again, Gobo goes to "Ice Cavern" or wherever, brings back some icicles and Boober grinds them up with a mortar and pestle to make ice cream with the other ingredients. Again, it's just a theory.
As for Traveling Matt not knowing what ice cream is, (confusing it for a moss pack), he's just comparing the shape of what he sees to something he knows. Fraggles might eat ice cream, just not out of edible cones because they don't know what they are.
To a Fraggle, ice cream in a bowl would be more familiar.
It's the same deal with the "very interesting cold bricks" Matt finds in the grocery store. (See the Grapes of Generosity episode). To him (and any other Fraggle), food comes from the Gorg's Garden or inside Fraggle Rock from ingredients. Manufactured food in boxes bought in stores is unheard of. Notice that Matt only recognizes food in its natural state. He has no problem eating grapes in the grocery store (a lot of Silly Creatures don't either, but that's beside the point). If the grapes were in a cardboard box with no way to see what was inside, Matt would just see an "interesting box" and maybe put it in the cart. He would recognize a tomato (having seen them at some point in the Gorg's Garden), but ketchup? That's paint for food as far as he's concerned.
If it were Gobo in Outer Space sending postcards back to Fraggle Rock, he would probably take more time to investigate and observe everything. He'd be more cautious and logical. Since it's Matt, though, the Fraggles have an even more odd view of our culture.
Convincing John