Are comparator ICs just Op Amps?
They are NOT op-amps.  Op amps have built in compensation to make them stable in linear amplifier applications.  This is usually done with a Miller-effect capacitor across an inverting gain stage.  That limits the slew rate (due to finite current available to charge/discharge the cap) and makes an op-amp a poor choice for a comparator.  A true comparator doesn't include the compensation cap, and will have other optimizations for the application. Another feature you might see in a comparator would be an open-collector output, which would not be useful in an op-amp.