I just read
an article from Mashable that might make sense of this move. It gives one compelling reason as to why Disney would want to buy Fox: Netflix. It was already reported earlier this year that Disney is going to remove a large chunk of it's content from Netflix in the coming years so it can start it's own streaming service. But in order for that service to work, it needs content. Even with the MCU and Star Wars and Pixar, that might not be enough to compete with the vast library Netflix has, which is still growing. In order to beat Netflix, it needs more and the content Fox has would definitely give it an edge.
Again, I still think it's very unlikely. It would bring up way too many anti-trust concerns. However, I do now see why Disney might push for this. I just don't think they will be willing to pay the necessary price it would take, which includes all the legal headaches that it would incur.