I can identify myself with your problems. They seem to be common with ISTJs.
Now on to the main point. 90% of the people I meet I dislike and want nothing to do with. The remaining 10% that I have a good gut feeling about usually never progress beyond acquaintance.
I've noticed that I practice a strong prejudgement on people, based on their looks, behaviour and interests. I feel that I'm pretty good at it, but I'm also doubting that it's kind of self-fulfilling prohecy. I might think that someone doesn't like me, and act in ways that will prevent from said person connecting with me, leaving the person at distance.
Few times I have mistaken with my judgements. The person I thought would be superficial or dumb turned out to be a fun and jovial person.
So now I'm trying to give each person a chance to prove themselves, before I completely judge their persona. It's not always so easy..
Now, my feelings towards most of humanity is very negative, and as I mentioned earlier, I dislike most people. I guess it's partway a gut feeling, and partway just seeing the negative in people.
Usually when you dislike a person you hardly know, it comes from some other misinterpreted feeling the person provokes in you. Could you be afraid, jealous or threatened by the said person? These feelings usually lead into a feelings of hatred.
Back in the elementary school, I was being constantly bullied by my class mates and failed to connect with most of the kids. That left me with thought that everyone who isn't my close friend, is a potential bully, who'd not like anymore more but to see me humiliated. That made me afraid of people I didn't know. And quite often that fear changed into loathing and despise.
I'm still, many many years later, having difficult of not despising people I find intimidating.
So I advice you to look into your feelings, and name all of the feelings these people provoke in you. I'm rather sure that somewhere along the line there is a reason why you hate people so much, and that's usually a product of an emotional wound suffered earlier.
Unfortunately, I'm also depressed. I dislike other people and I dislike myself. I'm not a very happy person. Is a less severe attitude of self-loathing and dislike of people part of being an ISTJ, or is it just something unique to me on top of that?
ISTJs seem to be pro at finding faults in things. It's a blessing for those who seek to improve and develop faulty things, but a curse for those who use it as their primary information source for human interactions. Trying to see the good in people will help you more, than finding possible faults in people.