I do not see any screenshots or text on the WordPress.org page for this plugin to give indication to people that this plugin will add such link before they try it.
Point 10 at http://wordpress.org/plugins/about/guidelines/ states:
The plugin must not embed external links on the public site (like a "powered by" link) without explicitly asking the user's permission. Any such options in the plugin must default to NOT show the link.
If you believe a plugin is breaking the rules for inclusion in the WordPress.org plugins directory, please send an email to the plugins team: plugins (at) wordpress.org