The meta charset information must also be the first child of the <head> tag. The reason this tag must be first is to avoid re-interpreting content that was added before the meta charset tag.
But what if another tag also specified that it had to be the first child "because ..."? Maybe that hasn't happened yet, but it could and then you'd have to decide which one truly was more important to put first? (Hopefully/probably it wouldn't even matter that much.)