Look Windows 1.0 to Me are properly called DOS/Windows because they relied on the work of DOS to provide the basic operating system routines, first compilers, toolchains, and driver infrastructure.
To call it just "Windows" doesn't do justice to DOS and its important contributions to Windows that can still be felt today in cmd.exe (NT based Windows should not be called DOS/Windows, however, it's of a different lineage and does not require DOS).