Postgresql runs a database server. That's it. Postgresql doesn't include a mailserver just because it needs to send alerts.
Apache runs an HTTP server. That's it. Apache doesn't include DNS and OCSP servers just because sites hosted on it will need name resolution and certificates.
OpenOffice, I'll give you that one. It combines multiple applications into one for historical reasons. I don't like it, but I don't use it so I don't have a dog in that fight.
Monolithic (in the sense used here) implies the combination of multiple essentially independent functions into a single application. Just because Apache and Postgresql are big applications doesn't make them monolithic.