A runner who commits an unsporting act might be ejected but not be called out. Coach would ordinarily send a substitute (NOT a courtesy runner). See 3-3-1-g PENALTY, which mentions ejection but no out, and 3.3.1 HH, which applies the provision and explicitly permits a sub. The ruling in 4.4.1B refers to a "courtesy runner" rather than a substitute because the team has no eligible subs to replace the injured player. I would extend that "courtesy" to a team with no subs whose player was ejected rather than injured on the grounds that, since there is no provision to call the ejected player out, somebody has to finish running the bases for him. You don't need to extend the case play from "courtesy runner" to "substitute." The rule itself specifically allows for this type of substitution. Whether the circumstances are correct for it to happen is the question.