To get to the point, I often get the vague impression that I'm not really becoming more liberal in my reasoning or viewpoints: I'm just learning how to mimic a system of protocols that comes in a book entitled, "How to act like a liberal in twenty-two thousand, four hundred and seventeen easy steps!" Maybe it's some weird from of impostor syndrome: if I behave like a liberal, it's mainly because I'm following a script so the other liberals will think I'm one of them. I mean, I am usually very guarded about how I speak and about how I choose my battles: it's probably affecting me more than I know. But, I still feel like reason leads me to these conclusions, even if they feel a little unnatural to me.
This is not something unique to you - it's exactly what the 'liberal mindset' is. There are several different issues on which there is a considered to be a 'liberal' point of view in the US today. Some of these are interconnected, but some only very loosely, and some are completely tangential with no connection based on any underlying philosophy. I've seen many attempts to synthesis a common logic that binds all the issues together, but they strike me more as post-hoc rationalisations, and crumble before the realisation that, when you look at different places and different times, the same issues do not bundle together.
These clusters of ideas come from people joining together to fight political battles over common causes (into Democratic and Republican parties for example), and from hanging out more with people who tend to agree with them. The echo chamber effect causes us to reinforce one another's views; and also to come more in line on the views we do not share. The issues become social badges of identity that we consciously or subconciously adopt to declare ourr membership of the group.
I'm not sure how clearly I'm expressing the idea, but if you start out (for example) as a liberal who opposes gun control, you'll be the minority view amongst the people you consider your ideological allies. The people willing to support and reinforce your view are often those you consider political opponents; while all around you the message that your viewpoint on this is 'conservative', a label you have come to associate with something you oppose. There is a lot of subtle psychological pressure for you to conform your views to the tribe; and we are very good at rationalising away the reasons for why we changed our minds.