Who said they were?  They aren't, but the difference is that those liberal groups are not Catholic Groups who use their society's funds to infect our Bishops & promote their political agenda as though it were a Catholic Agenda and not a Republican Agenda.  

Such as with pro-life.  Illegalizing abortion is one option on how to deal with the immorality of abortion, & even though almost every country that has severely restricted access to abortions or illegalized abortions, has a higher percentage of abortions, these Knights still push illegalization as the only, or best response, & they push unfunding planned parenthood's non-abortion tax funding designed to help poor women's health.  

There is also the innate sexism that automatically exists in having a supposed charity which refuses to allow women to join and become Knights.  Does not sound like the Knights got the memo that Catholic means Universal-All are supposed to be welcomed, including all men & women.  That is the difference.