>You can't re-create an icon to circumvent trademark law.
That's not what's happening here. According to wikipedia it's public domain because:
>This logo image consists only of simple geometric shapes or text. It does not meet the threshold of originality needed for copyright protection, and is therefore in the public domain. Although it is free of copyright restrictions, this image may still be subject to other restrictions. See WP:PD ยง Fonts and typefaces or Template talk:PD-textlogo for more information.
You can't re-create an icon to circumvent trademark law.
Using icon to refer to an application is fair use.
I am not sure what's the point of having a public domain icon.