When it comes to moral obligation members of the Church can suddenly become very pharisaical in the sense of setting aside God’s commandment and the teaching of His Church in favor of their own thoughts on how things should be done. We see people trotting out fragments of what Popes, Councils and Saints have said on a subject and using those fragments to justify their behavior against what the Church actually teaches. The result is that we see some people arguing that a Church teaching concerning rare circumstances like the Pauline Privilege justifies divorce and remarriage in the case of a Sacramental marriage, or that the Church teaching on Double Effect and hysterectomies and ectopic pregnancies justifies sterilization and abortion. When the Church responds to that argument with an emphatic “No,” people accuse the Church of hypocrisy, contradiction, and double standards.
Or (so people won’t think this error is only committed by people on the political “Left”), we can see people scandalized when it appears that the Church has said for the longest time that people must abstain from meat on Fridays and now they don’t, or that the Mass must be celebrated in Latin, but now it doesn’t. They accuse the Church of “changing” her teachings and falling into error.
Basically, people see the Church as “changing her teachings” in one area and either demand (or fear) that this means the Church can change her teaching in any other area.
But nowhere do we see people actually seek to understand why the Church offers X as a general teaching and then appears to say “not-X” when it comes to certain cases.