Adding tons of gain to any kind of source material, be it synthesizer, guitar, bass, vocal, drums, you name it, is going to clip the waveform, thereby naturally compressing the signal. So does that mean there’s no point in compressing a distorted signal? The answer is, it depends what you want to use compression for.
Since the natural compression caused by clipping/distortion will naturally limit the dynamics of your source audio, you may not need to add compression in order to control the dynamics of the signal further. However, compression is also often used to “glue” (or literally, “compress”) multiple tracks together. In this case, light compression can be used to further even out the dynamics of the multiple tracks and process their attacks together, helping the tracks to sit better in the same audio space. In this case, compression can still be used to great effect, helping multiple tracks — distorted or not — work together sonically. So you probably won’t need to control the dynamics of a distorted track as much with compression, but you still might want to use it in the mix.