When I add "import" keyword to section declaration, does FASM automatically define "data import"?

Yes. This is the same as if you put "data import" just after the "section" directive and "end data" just before line declaring the next section.
This feature was left mainly for backward compatibility, as the very ealy fasm releases (1.1x) didn't have "data" directive and it was the only way to make some special data directories for PE format. But it's still useful, as it simpler to declare such data this way when you want a separate section for it.