How to turn off ?do=print pages ?

I dont think these offer any benefit anymore. How can I turn these pages off?

These do still offer benefit. For example, I use print on recipe sites and other web sites I want a hard copy of, and I prefer not having the web site's full header, nav, sidebar, etc printed out too.

You may not need the button at the top of the wiki page, but you still need ?do=print to exist and have its own stylesheet. It would be triggered automatically by modern browsers when using File > Print, rather than having to click a button first.

I see the stylesheet for XenForo 1.x could use some improvements.

You can remove the button by creating your template modification for vw_node_title, and removing the section relating to $node.canprint

Are these pages set to noindex and canonical? I ran a SEO analysis tool and it considered do=print page as duplicate content, lacking meta-data.

Just looked at the output, and the printable target has a noindex meta tag, and the canonical tag is set to the normal version of the page. So you should not be hit for duplicate content.

Printable pages are designed to have very sparse HTML, so I am not surprised that it lacks metadata. However, since it shouldn't be indexed, it doesn't really need any.

Your SEO analysis tool may be confused by the Print icon which has a rel "print" rather than nofollow. It looks like rel "print" was removed from HTML5 in recent years. We use some other rels elsewhere that have also been removed from the living standard over the years, so we'll have to update some of these links.