Well, to quote the website:
The Critical Parent Role (sometimes referred to as the 6th function)
The critical parent role is how we find weak spots and can immobilize and demoralize others. We can also feel this way when others use the process that plays this role. It is often used sporadically and emerges more often under stressful conditions when something important is at risk. When we engage it, we can go on and on. To access its positive side of discovery, we must learn to appreciate and be open to it. Then it has an almost magical quality and can provide a profound sense of wisdom.
In me, I only have perhaps one to two true values I hold dear. One of them, is that my homosexuality is of no fault of mine, but a part of God's plan, and is a blessing to all those who have it. (not saying heteros aren't blessed of course). So, I frankly look for that in someone. If I don't like someone, I may use that as to why I don't like them. I really don't like them. BECAUSE THEY'RE HOMOPHOBES! (Note, that may not necessarily be why, mind you). And I can go literally go on and on about my one or two values and how I hate everyone who doesn't use them and their stupid ignorant useless pitiful blah blah blah.
Our last 4 functions are rarely productive, we tend to use them awfully. In fact, I am going to make a video log of how I use my 8 functions, if you want I can give the the "time" in the video of when I discuss my Fi. But I tend to essentially go overboard, just like a critical parent might. They might ground you to your room and take away all of your rights to live, for getting a B on a spelling test. I may find you a despicable person and not want to interact with you whatsoever, because you don't follow my personal beliefs. (Mind you, this rarely happens, this is only when I use my Fi. And I'm also using it with my Ne as well, which is why its so bad, its like I'm trying to be an ENFP, and just failing at it.)