Thumb Downs should be given two options: "I don't like this song." and "This type/style of music is not a match for this station." Actually, add a third option: "Both applies."
The song itself can be not liked but the style matches the station. It can be liked, but the style isn't the right fit for the station. Or it could be both: not liked, and don't want similar!
In the same vein, even Thumb Ups should also offer options: "I like this song, but do not use it to tailor the station." and "Yes, play more of this song and play similar."
Moderator Edit: Changing title for clarity
Of course, not Thumbing at all just leaves it be, as a neutral, with the station's running algorithms.
