As a bilingual Swiss-American, I would have to agree with the correspondent. The translations often do not seem professional but translated word by word into English, ignoring English syntax and usage. I do not know whom the ETH relies on to do its translations. If it is "merely" a native speaker that may not be enough. I know from my own experience how difficult, not to mention time-consuming, translating is. Possibly the ETH could/should hire a professional translator, for instance from the Fachhochschule Winterthur.