Individual politicians care about getting elected in addition to caring about their party having the majority. The gerrymandering means that in the district of an orange politician you would get 90% oranges if that would be possible to gerrymander.
In practice EY ignores that there are primaries. Orange politicians do have to face primary challengers and pander to their base. This means that there are forces to have more extreme orange politicians than you would otherwise get.
Individual politicians care about getting elected in addition to caring about their party having the majority. The gerrymandering means that in the district of an orange politician you would get 90% oranges if that would be possible to gerrymander.
In practice EY ignores that there are primaries. Orange politicians do have to face primary challengers and pander to their base. This means that there are forces to have more extreme orange politicians than you would otherwise get.