If you want to exclude a category in the featured listing, then you can do that by adding a little addition to the loop in the index template for your featured listing.

By default your loop look like this:

{{if \count($articles)}}
	{{foreach $articles as $id => $record}}
		{template="entry" app="cms" location="database" group="jwse_standard_featured_listing" params="$record, $database"}
	{{endforeach}}
{{endif}

This simply loop through your articles and then output them using the template listed in the group parameters.

To exclude a category we add a query to say that only categories not belonging to one or more categories should be displayed.

{{if \count($articles)}}
	{{foreach $articles as $id => $record}}
		{{if $record->container()->_id != '74'}}
			{template="entry" app="cms" location="database" group="jwse_standard_featured_listing" params="$record, $database"}
		{{endif}}
	{{endforeach}}
{{endif}}

You will need to replace the ID with the ID you want to the actual ID you want to exclude.

This is not a perfect solution however because what this does are that it will not give the articles with the excluded ID a template, so it will just not show, but it will still be counted. This leaves gaps in your listings, so I will look at a better solution to get rid of that.