Attack ideas, not people.
In a democracy with free speech, attacking the opposition with anything other than words is a tactical error; it draws attention to the muppet and creates sympathy, while hardening the resolve of their supporters as the oppressed underdogs/victims. Even if said muppet is cynically exploiting fear/prejudice/etc to advance their cause.
It's a mistake to focus on the singer, not the song.
Also, total waste of a milkshake.
If you don't live in a democracy with free speech, however, milky beverages are not going to work. Hong Kong Add Oil!