"Commercial" just implies commerce; that it was a product that could be purchased. It was not a consumer product. In the article it says the title was "Industrial Laundry Rust Remover".

There are certainly much nastier chemicals used that this in industry. As an example, I'm reminded of a quote by Gordon Moore about Intel having melted their sewer pipe, in this article:

https://www.bloomberg.com/news/features/2017-06-15/american-...