CaptainSauce
Super Poster
Other companies don't do this because they have respect for let's players. Nintendo is essentially saying "if you want to promote our product, you need to pay us". Everyone else either lets you do it for free, or pays you.
Nintendo is all over the place and seems to be on a case to case basis. Some people make lots of videos without problem, others have their stuff taken down, blocked in certain regions or more commonly have 100% of the ad revenue taken. I personally stay away from everything Nintendo, at the very least to not support them in their ludicrous policies.