How do you remove the ability for a user to make a comment or post on a page?

Since you want comments on posts, I would suggest that you not change the discussion options in the Settings section, but you can enable/disable comments on a per post or per page basis.

In the admin area, click to edit a page that you want to restrict comments from. Then, when you scroll down the page, you will see a section called ‘Discussion’ and you will have an option to disable comments or trackbacks. If you do not see ‘Discussion’, scroll to the very top of your page, click on ‘Screen Options’ and make sure that the checkbox next to ‘Discussion’ is checked.

Note: Depending on your theme. Your page might display ‘Comments Closed’, or something to that effect. If that happens and you want to remove that text, you might actually have to get your hands dirty and dig into your Pages template.