Why isn't "he is purple" accepted?
Agreed that most of the time it would be an "it", but there are times when it would be "he", for example, when talking about a toy or cartoon character, or somebody who's face is purple because he's very angry!
You are right, 'he' should be accepted! Tick 'my answer should be accepted' when it comes up again.
It is accepted now
'S was again flagged as a typo. If they don't want you using it, they shouldn't give it as an option.
"It's/He's purple" are both in the database as accepted answers.
If Duo is flagging either as a typo, then there may some underlying problem in the wider Duo system which is waiting for a fix.