Why isn’t there a “Write message” button on some users’ pages?

Privacy settings let users hide the Write message button from unwanted individuals, or simply from users that aren’t in their friend list.

If you don't see this button on another user's page, this means that you fall under Who can send me private messages restrictions of this user’s privacy settings. As long as the user has these settings enacted, you won’t see this button on their page.
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