Amen brother! Nothing worse then some JS based APP using 2G/3G in Africa. Its not about speed but latency and packet drops :/ No one optimizes for this stuff. Makes the internet unusable even if you have nice bursts of 100kb-2mb/s sometimes.
You should read the rest of the article and realise the author actually agrees with you. The comment you are replying to is taking the quote out of context.
You can write wonderful JS-based offline-first apps.
The question is not whether you can, but whether you will.
Whether others who wrote the app you need to use did?