Depends on where you're from - and several other circumstances.
If you're from the UK, it's an offence to take someone's property with the intent to permanently deprive them of it - so binning it after stealing it would qualify. Whether it's a crime depends on whether you get caught and charged with it or not.
What's worse? Committing a crime by binning someone else's perfectly good shirt, or averting a crime against fashion by binning the sort of shirt Eddie Jordan would normally wear?
I feel like if you called your local police station/constabulary/Sheriff's Department/State Trooper Post/Caribineri office; They would laugh at you.
"May I help you?"
"I'd like to report a crime?"
"What happened?"
"My friend got his shirt thrown in a bin"
"Where is it now?"
"Oh, my friend got it back"
-click-