It has nothing to do with EI. The game was on MY9 and you do not get MY9.
Unfortunately, you live in an area where Baseball (not Direct, not EI) determines you are in the NY DMA. Therefor the feed from the other team that plays the Yanks is blacked out in your area (MLB rule and has nothing to do with EI). The one time a week when the Yanks are on MY9 you cannot watch them since you do not get MY9. The other 6 times they are on YES, you can watch them (that is up to 6 times more a week than Dish subs can watch them in your market).
ETA: Usually the MY9 feed is provide on EI. If it is, are you able to watch that feed on the EI channel? I now I can and I do not live anywhere near the NY DMA