This really requires a statement from Microsoft - which I can't find.
Microsoft have cared much for compatibility for many years, so it seems unlikely that they will abandon the older CRT functions any time soon. I think they are just pointing out, in a strong fashion, that more secure functions exist.
Significant enhancements have been made to make the CRT more secure. Many CRT functions now have more secure versions. If a new secure function exists, the older, less secure version is marked as deprecated and the new version has the _s ("secure") suffix.
Pelle