It's not necessary for something to be a single binary for someone to call it (and for it to be) "monolithic".
Each utility in GNU coreutils is useful indipendently from the others. If each systemd binary is (almost) useless outside of systemd, systemd may not be a monolithic application, but it may still be a monolithic system.
It's more a matter of coupling than a raw number of binaries included.
Yo bro, a bunch of subroutines put together to form a program aint monolithic bro, you can use them seperate bro. They just happen to be used together bro!