Harry eats rubbish? I object! (9)

I believe the answer is:

protester

I'm a little stuck... Click here to teach me more about this clue!

But I can't explain it at all! Could you help me understand?

(Other definitions for protester that I've seen before include "Person, we hear, not content" , "Demonstrating kind" , "objector" , "I strongly object" , "Demonstrator" .)

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app