of course he knew how it would look.
the way satanists operate, though, is through deception. they tell you who they are and what they are doing, but then tell you a lie to follow it up, a spin. they revel in the deception.
so, with all the noticing going on, I'd bet that we'll get some bullshit spin that the red represents his grief from Diana's death, or some such nonsense.
they will use the shock and unsettling that it causes to reinforce their programming too. so, they may say that anyone who thinks it's satanic is a conspiracy theorist or a loon. "pay no attention to what your eyes see and ears hear, only believe what I tell you to believe…"