Trump needs to be careful that his regrouping after Iowa is focused on moving forward.
I agree, more or less - this is Carson’s fight, and Trump should keep out of it ... OTOH, if Carson lost a sufficient number of support b/c of this action - and those votes went to Cruz, it is possible that either the percentages for Trump and Cruz would have been much tighter - or that Trump may actually have squeaked ahead of Cruz ... In that context, Trump does have an argument.
I’m not stating that Trump would have won if not for this dirty trick, but I am suggesting that Trump does have standing.