That is because you have to sub to Extra Innings in order to see the games on Yes if you live outside of NY. With any pro sports and their blackout rules, you cannot view out of market games unless you pay for them through an out of market package.
Since Dish does not offer Extra Innings, then those outside of NY will not be able to see Yankee games on Yes anyway. The reason why people on this thread want YES because they live in the Yes local broadcasting region and are able to see the games without additional packages, if they had YES