Well, you quoted paragraph 34 but you left out paragraphs 33, 35 and 36, were the Bishops make it explicitly clear that you may not vote for candidates that support an intrinsic evil by appealing to their positions on other lesser issues like feeding the poor, or fixing immigration, etc.
There is only one scenario where you may vote for a candidate that supports an intrinsic evil and that is when the other candidate also supports the same intrinsic evil (see paragraph 36). In this dilemna, you may choose to either 1. Not vote or 2. Vote for the candidate that will do the most to limit the intrinsic evil in question. But, you may not appeal to secondary issues (economy, immigration, etc.) in order to make the decision, not when an*** INTRINSIC ***evil is involved.
Obama supported and supports the INTRINSIC evil of abortion on demand (as well as homosexual marriage). That ruled him out as a viable choice for Catholics by default. You can’t appeal to any positive things he may or may not do on secondary issues (immigration, economy, ect.) when he already supports and INTRINSIC evil on demand. The USCCB makes this clear in their Faithful Citizenship guide, paragraph 35:
There may be times when a Catholic who rejects a candidate’s unacceptable
position may decide to vote for that candidate for other morally grave reasons.
Voting in this way would be permissible only for truly grave moral reasons, not to
advance narrow interests or partisan preferences or to ignore a fundamental
moral evil.
Obama supports a “fundamental moral evil” on demand so you can’t ignore his support for it by appealing to any good he may or may not do reagarding less fundamental evils like the poor and immigration, etc.
The only viable choice was Romney, but Catholics did not HAVE to vote for him since he also supported the intrinsic evil of abortion in cases of rape and incest.