What does "simplicity" mean here?

I just read this article today:

It claims that “it’s simplicity has only created barriers”. Does this mean “the language being phonetic” has created barriers or what?

From the article:

Part of the problem lies in the language itself: Bahasa Indonesia has fewer words than most languages. Endy Bayuni of The Jakarta Post has written that foreign translations of Indonesian novels tend to read better, while Indonesian translations of foreign novels sound ‘verbose and repetitive’. But there’s also a political dimension. Because Indonesians learn Bahasa Indonesia in school, then hear it as adults primarily in political speech, they associate it with homogeneity, according to Dr Nancy J Smith-Hefner, associate professor of anthropology at Boston University.

Also from the article, here’s the paragraph from which the sub-headline was presumably drawn:

It turns out that a means to linguistically unite the Indonesian nation has instead, due to the language’s simplicity and rigidity, created a new barrier that prevents communication on a deeper level – one that Indonesians circumvent by employing their own particularised speech, tailored to their specific regions, generations or social classes.

So this seems to be about semantic nuance.

Semantic nuance of what?

The point being made is that Bahasa Indonesia is too simple to communicate as subtly and expressively as the regional languages it is intended to replace.

“Semantic nuance” simply means the degree of freedom to impart small variations of meaning (“semantic” means “meaning” in this context).

Imagine that the only word available in English to express being wet is “wet”. We would lose the ability to express any nuance in wetness. We would lose “drenched”, “soaked”, “moistened”, “damp”, and a lot of other words that convey variations on wetness.

If concise and expressive communication is important, people will avoid restrictive and inexpressive languages if they have an alternative. Hence, the resistance to Bahasa Indonesia in preference for the more expressive preexisting languages.

Obligatory XKCD.

Right - a potential pitfall of a “simplified” language deliberately intended for standardized common communication.

To be fair, from that article and other mentions I have seen it seems that what happens in the practice is that people casually among their own community still just use their own mother tongues, and use Bahasa Indonesia for formal/public communication, and in practice it will get “flavored” with words and grammatical forms of the local community’s or the individual speaker’s mother tongue. So in that sense it’s not that “nobody speaks Indonesian” but rather that nobody would speak the standard “book” version.

It is an easy language to learn. It took only a week or so for me to be able to bargain in the markets. I mean, who can’t love the onamatapaeic word for a flock of ducks, “bebek bebek”? And “orang utan” meaning “person of the forest”

However, my hosts there (girlfriends parents) were studying formal Bahasa, and reported that that is far more complicated and has many more tenses. They lived there for quite a few years and were in high-level academia, so they needed the formal form.

Really, it seems to me that the article you linked to answers your question.

If I remember correctly, Bahasa Indonesia was chosen as the national language both as a unifying tool and a way to prevent Javanese, which was the language with the most native speakers at the time (and perhaps still is), from dominating the others. Your article touches on this, in fact.