The same way that driving a motorcycle and driving a car are very different.
The same way that going to a theater and watching pay-per-view at home are very different.
The same way that wearing a baseball hat an wearing a veil are very different.
The same way that running and walking are very different.
The same way eating and drinking are very different.
The same way that reading and listening are very different.
Streaming video is fundamentally very different than streaming games. The interaction with them is different, the price people are willing to pay for them is different, and the data collected by external servers differ.
And lets not forget one really important thing: it's 100% Apple's call over who can list things in the app store, and they have every right to make distinctions between one app and another. Heck, Apple could set new rules about ads and remove Hulu if it wanted.