Note that the dependencies aren't because of setting the colour temperature, but to get your location information (see geoclue in the list). geoclue has several providers, but a common one for desktop machines is to connect to a network service that does geoip. Consequently most of the dependencies arrive due to that (eg proxies, crypto, glue code for object models to do all that, and some innocent bystanders).
The location information is used so that redshift can alter the colour temperature during the day (less needed) and dusk, evening and night (very needed).
The location information is used so that redshift can alter the colour temperature during the day (less needed) and dusk, evening and night (very needed).