What a terribly misleading post title.

The post title contains literally the entire OnlyOffice-related content of the article, which is titled “Why ODF and not OOXML”. Here’s the first paragraph:

Many interpreted the last article in this series as an attack on Microsoft for using the OOXML format against users’ interests. However, this was only one of my objectives, as I also wanted to raise users’ awareness of fake open-source software, such as OnlyOffice, which partners with Microsoft in a strategy to lock users in.

Everything after this is about closed vs open standards.