Why hasn't The Pope's criticism of Trump hurt him amongst Catholics?

[Famous Mortimer]

Because the Pope is a liberal.

[Famous Mortimer]

Because most American Catholics don't really care that much about the Pope.

Liberal/lapsed/CINO Catholics don't care what the Pope thinks.

Conservative Catholics don't like this Pope.

[Famous Mortimer]

Look at the numbers. Catholics can't stand the modern Republican Party, and they especially can't stand Trumpism.

Catholics mirror the U.S. population as a whole in terms of party affiliation, which actually means they lean Rep as compared to the regions they primarily reside in (aka not the South, largely). Once you get down to Mass-going Catholics, and those who largely agree with RCC doctrine, they become more likely to lean GOP, but still not to the extent of church going evangelicals.  Because of their multi-ethnic character and mixture of non-committed and committed members, they are a true swing demographic. It's admirable (to a certain degree) that they are not co-opted in the way many white evangelical or black churches are; their diversity prevents this.

As to whether the Pope's criticism matters...I'm sure it does to some swing voters. His problem was that he chose the wrong issue to call him a non-Christian over, or the metaphor he was trying to go for (bridges and walls) clouded the fact that he was talking about more than an actual wall. Those who are most likely to listen to what the Pope has to say are the most likely to realize that the Pope isn't a dictator who demands everyone do what he says on non-doctrinal issues. He should have made it explicitly a character issue. The problem with Donald Trump isn't that he wants border security, but why he and his supporters want it. THAT is a theological issue. Unfortunately Francis doesn't seem to want to take the time to consider putting some nuance into his statements.

Francis' frequent political commentary is also a double-edged sword. Rather than trying to please everyone (as JPII and BXVI attempted), it seems like he tries to piss everyone off. For the left, there is calling abortions for the health of mother/baby a "mafia" hit, calling the gay rights movement our generation's Hitler Youth, and comparing transgenderism to atomic bombs going off. For the American right, he criticizes business and nationalistic interests, and unlike JPII, doesn't seem to think the death penalty is ever, or was ever, acceptable. The fact that he speaks up so much about politics means that each comment has less weight than it might otherwise.

With all that having been said, I highly suspect that plenty of Catholics in Massachusetts will be casting their ballot for Trump today.

Liberal/lapsed/CINO Catholics don't care what the Pope thinks.

They care when he agrees with them. Which they pretty much do on everything now except abortion and gay marriage.

Contraception, divorce, transgenderism, women's roles, celibacy outside of marriage, celibate priesthood?

Those liberal/lapsed Catholics who actually disliked John Paul II or Benedict weren't angry that they didn't sufficiently critique capitalism and anti-immigrant attitudes. If they were, then they didn't have any basis for it, because both of the previous popes were quite strong on economics, the environment, and humanitarian issues.

Huh? What is that list of issues support to mean? You are proving my point. Liberal/lapsed/CINO Catholics don't care about the Pope's opinion on those things.

Furthermore, liberal/lapsed/CINO Catholics who are left-wing on economics and the environment are not left-wing on economics and the environment because the Pope told them to be. Again, they do not care about the Pope's opinion. That doesn't mean they aren't mildly pleased when the Pope, or anyone else, happens agree with them.