I get that Twitch is intended to be a gaming-focused (and apparently music as well) website. However, there are people who may want to stream other things. Even if these things are neither illegal nor morally wrong, the rules of conduct as they are now prohibit them from streaming what they want.

If the Twitch community is not interested in non-gaming/music content, they will not watch these streams. People who are only interested in gaming/music content are not being forced to watch these streams, and as such their existence does not negatively impact them at all. However, the existence of said streams does positively impact people who are interested in such content. Closing down these streams does not help anyone, but it hurts everyone who enjoyed them. Therefore, it follows that this rule is nothing but harmful to the Twitch community.

If you do decide to get rid of this rule, it is extremely likely that Twitch will remain a gaming-focused website. Twitch is strongly associated with gaming, and that is unlikely to change even if other content is allowed. Case in point: the rules say music-related content is also allowed, and Twitch is still mostly a gaming-related site.

Please get rid of this rule!