What are the complicated apparently contrived reasons?

It's not at all clear from the article.

All I really got from the article is "collabora are banned from contributing to open office, and aren't happy about it". What reason did they give? What's the actual reason you think it is (you mention things are contrived, so I assume there's another reason you think)? What's the libre office online stuff got to do with it?

All of this is unclear from the article.