This seems to be plagued with ISFJ stereo typing that is mostly not true. I could see an ISTJ maybe falling under these definitions, however this is not the greatest separation of ISFJ's and INFJ's.
ISFJ's are often thinking as well, and we often see the value in laws, but if we see a law as harmful, then we are not going to just step in line, just because its been around for a period of time. We are not mindless automatons. Si is a judging function. We are constantly taking in the details of things and comparing them with past experiences. We definitely care about what is fair and what is not, but what we see as fair might not coincide with what you see as fair. The underling principles are often important to us.
ISFJ's are just as likely to get fired up over a subject that resonates with them, yet they also pick and chose their battles because they we also value harmony. Just because an ISFJ does not disagree with you on the surface, does not mean they agree with you. They just want to spare your feelings and avoid unnecessary conflict. Likewise, if an ISFJ is quite capable of understanding the nuances of how a government should run, but it does not mean they are going to force their views of how things should run on others.
You can generally tell the difference between an ISFJ and an INFJ buy their speech and their mannerisms. Its hard not having a person face to face to type them properly. The best thing, I would suggest is to type a essay, of a descent length. Have others go over it and see what conclusions they draw and why.
