Headcanon: Equius is so committed to the hemospectrum because of his mutant strength. Higher bloods are supposed to be stronger than all below them, so freakishly strong Equius could be seen as a huge threat to highbloods and immediately culled if he showed any sign of believing himself better than his blood color. Either Equius realized this himself and committed himself to the hemospectrum for his own safetry, or Aurthour taught him it at a young age to keep him safe.
I’ll take it.
~Mod T