It moves like a normal knight but leaves behind a trail of fire for the next 2 turns. If any piece crosses or lands on it, they take 1d4 damage per turn in the fire.
S. Pyogenes can objectively cause nec fasc and toxic shock syndrome, both of which are life threatening. 20-30% of NEC fasc is Type 2 which is primarily S. Pyogenes or Staph.
S.Pyogenes is also one of the main bacteria that cause type 1 nec fasc which is around 70% of cases.
Calling it 'just strep throat bacteria' is inaccurate.
Its not even comparable, schadenfreude from someone getting heatstroke due to their own stupidity is not even remotely similar to wanting to kill people you don't like. If you can't see that then thats on you.
Getting a small satisfaction from people getting heat stroke due to their own horrible choices is not the same as wanting to kill all queer, immigrant, and brown people but nice try.