I thought the way Chomsky means it, "ubiquitous" and "universal" are the same thing. He isn't saying it's impossible for some aliens to develop a different sort of language. He's just claiming that all human languages share some properties, and those properties are genetically determined. It might be incorrect, but it doesn't seem arrogant and ridiculous. Plenty of human mental qualities are genetically determined across cultures, like reactions to a sweet taste or the sight of a snake-looking thing, so why not language?