Looks like a couple things you need to change up to help eliminate some issues with how Kentico handles SQL injection.
CONTAINS(Tags, '{%IfQueryString.GetValue("keyword, "") != "") { QueryString.GetValue("keyword", ""); } else { "no-tags"; } |(identity)GlobalAdministrator%})
Secondly, you'll want to sanitize that "keyword" parameter input.
Lastly, you need to make sure you have the parameter added to the alias of that page. Meaning you'll need to add an alias like below to get the keyword parameter to work:
/rss/{keyword}