’equalized’ is not the best choice of words by Kevin, he means equalized in strength, not in frequency adjustment as per RIAA curve.
the signals on the LP have been boosted (highs), and Cut (lows) as per RIAA industry curve, so a ceramic cartridge’s ’incoming’ and ’outgoing’ need to be ’riaa equalized’ as well as ’signal strength’ adjusted.
RIAA 'playback eq' occurs in the MM Phono Stage, to reverse the cuts and boosts that occured during 'recording eq'.
LP stands for Long Play, and Long Play is only achieved by cutting the lows signal strength so the grooves for bass cut into the master are not physically 'wide', thus the grooves can be closer together, increasing the total duration that fits on each side. The boosting of highs is for different reasons.
Line Level is an input, no frequency adjustment occurs, the original signal strength level to amps (before preamps were needed), was 1 volt.
IF you plug a KAB CERMAG out into a line level in, the highs will still be boosted, and the lows still cut.