As I mentioned earlier, I don’t know what Cardinal Ratzinger meant when he said that proportionate reasons existed. But in his mind, they apparently do. However, I do agree with you about remote material cooperation being of concern, and not something to be dismissed
He left open the possibility that there may be proportionate reasons which would allow one to vote for a candidate in spite of their pro-abortion stance. So let’s examine a situation in which there may be found a proportionate reason. Candidate A is pro-abortion. Candidate B wants to round up all disabled persons and euthanize them. I guess in that situation you could say that both of these are intrinsic evils so you could vote for the candidate of your choosing based on other issues.
But that still doesn’t get around the matter of “the five non-negotiables” being a political phrase not used by the Church. The bishop objected to a political tract being handed out in his parishes. Its not an unreasonable thing to do.