First, any "white" card takes away from a blue card. That should be obvious. But it gets more subtle when you look at the mechanics of voting a partial slate.
CP says "Don't check EJ...". There will be no such option. You must check "Withhold some" and then write in names of those you do NOT want to vote for.
But CP is already suggesting you select those you want to vote for, and leave off those you want to vote against. This action would vote the other way.