Apologies for not answering, I missed that post. You've articulated a situation where the law as written feels strict - but I don't think that's particularly relevant here.
An incidental gesture that an opponent has run into is not the same as making a deliberate motion in reference to another person. CH
knows Robertson is there and chooses to make an aggressive gesture with his arm in-and-around the space where he knows Robertson is likely to be. Moving your elbow rapidly into the space where there's a good chance someone's head/neck might be is
at the very least failing to consider the risks.
To drag back to another football example - a player can make 2-footed flying blocks at knee height in the middle of nowhere all day. As soon as he does it somewhere where he should reasonably expect an opponents leg might end up, they run the risk of seeing red.
(I appreciate this isn't your fault because you and
@zarathustra et al are different people, but it's very draining and confusing to alternately be told that I'm not allowed to apply the LOTG and to then be drawn into discussing intricacies of the LOTG to try and make the same point!)