I've never seen a version of D&D (or any other game) in which 'halflings' are anything other than re-branded hobbits. Hobbits are small, plucky, portly people (for all practical purposes).
Well, since 3rd edition they don't seem to look like hobbits at all in D&D...
Luckily, DCC isn't D&D, the halflings are based on hobbits as they should be.
It would be obtuse to suggest hobbits have the steel-wire strength of the monster from Alien.
It would be obtuse to suggest that an Alien has only a strength of 18. It would be obtuse to compare monsters, who aren't bound by the rules like the players, to the players.
Of course, anyone can make a race like that any time they want. But they aren't hobbits (er, 'halflings').
Well, if there are short people around us with above the average strength, then it makes sense to have strong halflings too. It still won't happen often, rolling an 18 for Strength is not that easy. And while demi-humans does have their own stereotypes, saying that my hobbits aren't hobbits because they aren't exactly like Frodo or Sam (who are quite the average Joes among hobbits) or like how you imagined them seems to be nonsense.
Halflings are short, sturdy, sneaky, peaceful guys in my campaing - if I tell one of my players they're hobbits, he will clearly recognise them. And if he rolls up a hobbit with 18 strength, he won't say that "this isn't a hobbit anymore", but "cool, I have a strong hobbit, maybe he was the local bully". If you feel this is wrong, then feel free to change them in your game, but don't tell me I'm a fool because I can imagine having a strong hobbit.