That has nothing to do with anything.
Discount the fact that MLB personnel were in the video room during the playoffs,
"...The Astros could only pull this off during home games (when they had access to the video feed). As a result, a number of Houston players had way better stats at home than on the road."
Stands to reason that the Red Sox could only "pull it off" at home as well.
Be that as it may, if Cora broke the rules in Boston and/or in Houston, he should get what he gets, especially if it is a written rule and his club was the reason for the original warning memo. Doesn't matter to me. It's all entertainment to me at this point.
I won't absolve MLB though. How in the world do the powers that be expect the franchises to self police in this fashion, less than two decades after a PED scandal that had it's roots in the early 1960s.
Unwritten rules are not rules and are not enforceable by a governing body. Unmonitored behavior is de facto allowable. MLB is being pretty hypocritical. If it were really important, they would station an MLB employee in each video room immediately following the first memo.