I would argue that the consistent principle is to protect the right to freely express ideas, arguments and points of view, no matter how stupid or poorly supported they may be. _That_ is what should be protected; not the literal interpretation of "anything that comes out of a mouth".

Most of the things you list are not about expressing ideas or making arguments, they're mostly about breaking contracts. Those that are not, e.g., holocaust denial, are precisely the contentious and dangerous ones.