[Plugin: Contextual Related Posts] Exclude by Category?

Yes it does. You need to enter the category slugs. Start typing and it should pop-up a list based on what you type.

Posts in these categories are excluded from the lists.

I’m sorry. My prior statement was completely off.

What I meant to ask, is if there is a way to physically exclude the plugin from the bottom of particular posts? I don’t want the plugin to be shown on specific posts (‘portfolio’ category slug). Not just exclude specific content–but to exclude the plugin entirely?

You’ll need to do a manual install. You need to deselect the “Add to posts” option.
Edit your theme files and use the code.

In the single.php within The Loop, add a conditional code. Check: https://codex.www.ads-software.com/Function_Reference/in_category