Windows thinks the computer is a touchscreen device like a tablet. The message is hardcoded in Windows, controlled by Windows, and the content cannot be changed.
As I noted in my answer now deleted by an admin who thought a useful answer was less good than the only other answer which was not applicable, there is a thread at https://social.technet.microsoft.com/Forums/en-US/7d14c6de-445d-4ace-95d3-dccf0f80e558/change-secure-sign-in-message?forum=win10itprosetup that talks about computers needing a BIOS and/or some Intel HID Event Filter driver updates to fix the issue on Dell laptops. This thread has no directly useful information for permanently solving the problem; it merely talks about the problem being known by both Dell and Microsoft, so yours is not a one-off or unusual problem.
The answer is as stated above and in my original answer, now deleted by somebody else because they're smarter than me, and which I'm not allowed to undelete: update your BIOS, apply all driver updates from the manufacturer, then apply all Windows updates, and the problem will hopefully go away -- at least it did for the 20+ laptops I had the problem on.