Why is executing Java code in comments with certain Unicode characters allowed?

The following code produces the output “Hello World!” (no really, try it).

public static void main(String... args) {

   // The comment below is not a typo.
   // \u000d System.out.println("Hello World!");
}

The reason for this is that the Java compiler parses the Unicode character \u000d as a new line and gets transformed into:

public static void main(String... args) {

   // The comment below is not a typo.
   //
   System.out.println("Hello World!");
}

Thus resulting into a comment being “executed”.

Since this can be used to “hide” malicious code or whatever an evil programmer can conceive, why is it allowed in comments ?

Why is this allowed by the Java specification?