When clicking on the three dots on a specific post, the share icon is displayed. This takes you to the sharing extension built into mac. However, Apple is dumb, and the sharing extension is not able to display the ability to copy a link or text or anything. This makes it impossible for mac users to copy the links of specific posts unless you click on the "Comments" button and copy the page url.
Right clicking on the timestamp of a post will get you a shareable link