It’s semantics really, isn’t it?
The intent is to let people know that you can follow the link and listen to the song without handing over money, and I’m sure that’s how people understand it. They know what site they’re being sent to via the link and can make their own assessment. ‘Can be streamed legally’ might be more technically correct but I don’t see the benefit in a practical sense, and maybe a bit more confusing (do we guarantee that our links are legal uploads, and a paid stream, eg a iTunes purchase, also falls under the definition of ‘legal stream’).
Disclaimer: I also strongly believe Spotify is satan manifested on earth as a music “service” 
At least the semantics are right for Bandcamp!