The Google wordlist has lots of examples that aren't about offense, like use of hyphens and brand names. My guess is that "senior citizen" is considered Americ

The Google wordlist has lots of examples that aren't about offense, like use of hyphens and brand names. My guess is that "senior citizen" is considered American English, so it's a poor choice for global audience. They even write "avoid figures of speech" to clarify that section.