SJs are "guardians" of how they were raised. SJs with hippy parents tend to be hippies, too. SJs with conservative parents tend to also be conservative. More or less. The main thing is "how they grew up and how they were taught".
Si types tend to "think inside the box" and have difficulties thinking "outside of the box", so most of their understanding depends on what was put in that box to begin with. As Si types mature, Ne starts coming into play more and more, and they get comfortable with thinking outside the box, but tend to rely on that core Si box. Changing what's inside that Si box is very difficult for them to do (but it IS doable, it's just very difficult and painful to process).
In contrast, Ni types tend to "switch out boxes", where they have a huge library of possible "boxes" or "templates", and overlay those templates on what they see, and then deduce which template is correct based on how well it matches up. (The tough thing for Ni types to give up is a bunch of "boxes that work", but it's difficult to even tell that that is what the problem is and communicate it to them.) As such, Ni types will tend to have political views that are out of sync with both right and left - and not necessarily in a good way (think conspiracy theories). In political threads, I see Ni types tend to be more extremist and ideologically pure, but with only very specific colors on the left/right spectrum. I see pure socialists, pure communists, pure capitalists, pure libertarians, all arguing condescendingly to each other on forums like INTJf.
Se types are more like, "Dude, why are you worrying about boxes, man?! This is real life. You can't put life in boxes!"