First: it's because it's making cultural observations about the people from both places, and trying to somehow say that this is reflected in the language.
For the sake of argument, let's just assume the British are "less emotional" than the Argentines (though attending a football match in each country may disabuse you of that idea). This may affect the way people use language, but it does not affect language. Language is a tool that people use to convey their thoughts. The tool not affected by the thoughts it is used to convey.
Second: sure, English may have lots of one-syllable words for things that are two syllables in Spanish (though the "lol" example you gave above is spurious because in my experience people just write "jaja."). But English requires more use of pronouns, articles and prepositions than Spanish does:
* "No sé" vs. "I don't know"
* "No lo vi" vs. "I didn't see it"
* "vamos" vs. "let's go"
* "saco la mano" "I take out my hand"
What's more "efficient?" It's subjective, and at the end of the day an utterly meaningless thing to analyze because trying to extrapolate cultural behaviors from the way a language uses propositions and articles is about as good science as phrenology or astrology.
Third: let's assume when people say "efficient" they mean "simpler grammar." People often claim that "Latin is more complex than English" because it has nominal declensions. But because of its declensions, word order in Latin is almost irrelevant. In place of declensions, English uses strict word order to distinguish subjects from objects. Which one is simpler? It's subjective, because your answer will depend on whether you're a native speaker of a language more like Latin or more like English.
But if you're writing a program to parse natural language syntax, Latin's "complex" nouns make it a lot easier to parse programmatically than English. What does this say about Roman culture? Nothing. Again, it's the wrong way to look at language - there's no valid reason to draw a connection between grammar and cultural behavior.