This list is bizarre. What is the metric that they are using? It's not revenue, profits, assets, or market value. Is it an algorithm of sorts from Forbes? Even then I have to ask why AAPL is 6, MSFT 16, GOOG 17, and AMZN 28.
Aside from being the 70th biggest company in the world, as already mentioned, I also can't find any other purely entertainment oriented companies ahead of Disney on the list above. So unless I'm missing one, I guess they're the biggest entertainment company in the world.
Warner is owned by AT&T which is larger than Disney by all relevant metrics, i.e. market cap, EV, revenue, and profit. I guess you can make an argument that they are a lot more diversified than Disney due to their telecom business, but I would still say from an objective measure they are the biggest entertainment company in the world.