I don't know if you've ever attempted dialoging with someone who claims to be a liberal, but it can be a very frustrating experience.
Not long after I became editor of what was then the Times Review, now The Catholic Times, the newspaper of the Diocese of La Crosse, one of the regular columnists submitted her column for publication. I read through it and it had an interesting beginning. She was meditating on the fact that in older houses, the most worn part of the floor is in the kitchen and that in churches, the most worn part of the floor is the center aisle where we receive Communion. This isn't something I would normally connect and there was potential here for something really good.
But then she veered off-course. She started talking about the "altar-table" and the First Communicants who were going to be "confirmed in their holiness" by the reception of the Eucharist. "Hmmm," thought I. "Where in the tradition is the altar referred to as the 'altar-table' and since when did the Eucharist confirm our holiness and not confer holiness to those of us who are desperately in need of it (which is all of us)?"
So I wrote to her asking her to support what she was saying. Where in the tradition or where in the documents is the altar called an 'altar-table'? Where in the tradition or where in the documents is it stated that the Eucharist confirms our holiness? The letter was quite polite and I was asking in genuine curiosity because she had a Master's in theology and I figured she had read something somewhere that gave that information.
The letter she wrote back, if memory serves me correctly, was rather terse: "I believe that at this time, it is best for me to move on," or something along that line. Fine. But that didn't answer any of the questions I asked with sincerity.
Assuredly it's not only people on the "left" who have this problem. There are those who will say, "The Bible says, I believe it and that settles it." But at least they are going back to a time-tested source. The problem with the left is that many of its typical ideological adherents are proposing all sorts of novel ideas without any indication that this novelty has support in the human tradition.
We humans cannot simply make up something out of thin air and expect that it's going to serve humanity well. There are reasons we do things and reasons we don't do things. We marry one man to one woman because millennia of human experience have shown that to be the best way for us to continue our existence on this planet and to build our society. We don't allow men to have sexual relations with men or women with women because human experience has shown that it can't produce children and it's not stable.
This is what is so difficult about trying to have a discussion of any substance with someone of this mindset. They make up the rules as they go and if you don't play along, then you can forget about discussing why they're doing or saying what they're doing or saying. So when you get down to the brass tacks, they're assuming an awful lot of power -- not unlike the power God has, which is not a good place to be.