They retitled the piece is “All Catholics Have a Moral Obligation To Vote Against Hillary Clinton” but you can plainly see what they are really trying to do from the URL: https://www.catholics4trump.com/all-catholics-have-a-moral-obligation-to-vote-against-hillary-under-pain-of-mortal-sin/
This is, not to put too fine a point on it, a lie. It would, by the way, be a lie if I likewise told you that you had a moral obligation to vote against Trump on pain of mortal sin.
Why? Because the reasons people choose to vote are so complex that it is impossible to say that somebody is committing mortal sin. And, in fact, the vast majority of Catholics are voting, not because they get up in the morning thinking, “How can I commit a sin worthy of the everlasting fires of hell?” but because they are trying their best to do the right thing. They have differing modes of moral calculus but are trying to do the good.
For example, it is obvious to some of us that Donald Trump advocates all the evils Hillary Clinton does, plus numerous evils she does not. It is a manifest and documented fact that he lies far more than she does and that he regard the prolife movement as useful idiots to whom he can tell faint and unconvincing lies and they will bend over backward to believe him. And it is plain that the ridiculous attempt by Catholic4Trump to coerce a vote for him on pain of mortal sin is ridiculous on its face and a disgraceful assault on scrupulous Catholics struggling with their conscience when it tells them that Trump is fraud who will destroy for a generation the tattered credibility of conservative Christians who use such foolish tactics to compel and coerce votes.
And so, in the words of Cardinal Ratzinger, it is perfectly legit in such circumstances to try to lessen the much greater evil Trump will certainly do by working to defeat him by a vote for Clinton: “When a Catholic does not share a candidate’s stand in favour of abortion and/or euthanasia, but votes for that candidate for other reasons, it is considered remote material cooperation, which can be permitted in the presence of proportionate reasons.”
Note to scrupulous Catholics troubled by this bullying and abusive lie from Catholics4Trump. Listen to Cardinal Ratzinger. You don’t have to support Trump. And if voting for Hillary seems like the best way to stop him, you are free to do so as long as you are doing it to stop Trump and not to support the evils she does. Only one of them will win and if, like me, you have the conviction that it must not be him, then you can vote for her with a clear conscience.