The part everybody is missing is "I'd actually like to go back to the old times of Tudor England", which provides the context to understand the stuff people is having a meltdown about. This is not "heads on pikes" by a bunch of salvages; it is "heads on pikes" as part of the official policy of an absolutist State.
The way I read it, Bannon said: "I would have them face the death penalty, if there was a legal way to do so. And I would use their cases as deterrence from other would be traitors."
I don't see it as a call to have civilian supporters attempting against the lives of those two high ranking officials; but could be interpreted as a declaration of intent to pursue and extend draconian powers for the (Executive Branch of the) US Government. I will let you decide which of the two interpretation is gravest.
How do we interpret this next sentence as a continuation of the figure of speech? I can't seem to wrap my head around it sounding anything other than explicit.