Offended and uncomfortable I can understand, but I don't see what is scary or threatening about any of what you have (mostly correctly) summarized, unless it's just fear of the unknown, as others have mentioned.
Fear of the unknown is certainly a factor.
People dont like talking to a predator. It is a stupid thing to do. They might use what you say against you- especially if they seem to only need a little information and somehow magically get a hold of the rest. For that matter, even if youre secure enough that you can handle yourself, is not fun to endure that kind of conversation where yoy feel like the ant.Not to mention its a fucking useless convo as they refuse to share the info and make you feel like a moron in the process.
But most importantly, our species is a collaborative one. And it is the failure or refusal or unawareness of the need to establish an actual rapport to foster even the most basic trust between you and your tribesmen that is at the base of their response to you, and at the base for their - imho at least somewhat legitimate - perception of you being a potential threat.
People pleasing and accomodation is the norm in a multi-individualed culture like ours - one you dont even seem aware of or if you are, you seem to indicate that all the bending and flexing should come from the other person. That kind of behavior is normally only employed when there is no time to argue and people are expected to fall in line for their own good -and preferably by a leader who has already proven he has the groups wellbeing in mind and has earned goodwill from most of the people there. It s an almost instinctual response. So what is it the intj is seeing but not sharing that requires this falling in line - especially as building goodwill is bypassed. It must be urgent and important as he seems quite serious, adamant, confident about this and competent.
And, can i trust him at all, considering the conversation gave me the feeling that im just a pawn to him anyways. A stupid one at that. Is my wellbeing even considered by this person or am i just collateral damage. Iow, the herdlike insecurity you -as an intj- cause in a person can target their self esteem, their sense of safety, cause paranoia and other fears. Which in turn leads to resentment and feeling like a fool making you the asshole who stressed them apparently just for fun, just coz you couldnt take two seconds, focus on the connection with the person in front of you, establish some goodwill through that warm focus and make them realise you do recognize them as one of your own instead of as an object, prey or cannon fodder.
Its kind of normal to be part of the group and demonstrate that you are as a social animal so others know where they stand with you, and what to expect from you. And that natural need and communication of that kind of basic reassurance seems to pass you by. Which in turn is likely to get you the 'who the fuck are you response fom assertive people and fear, paranoia and avoidance from those that are conflict avoided.
in essence, you're depriving them now of two pieces of information: the information you get through Ni about the situation, and information as to their status with you (Fe information). Lack of information can get you killed. And someone who seems to be deliberately withholding that information from you doesn't exactly inspire a lot of trust, so the INTjs ulterior motives and agendas will be speculated on to make up for the gap in information they're creating.
It's the difference between being invited to an audience with the Godfather, with you sitting down in front of him and him staring you down as he lays out how it's going to be - without informing you what he intends to do with you afterwards, and having a friendly chat with someone you just met who is smiling and inviting you to sit right next to her on a bench. You bet it is threatening and intimidating.
Disclaimer: this is meant as a description of what goes on between people who don't know each other and in a situation where the INTJ would not naturally show warmth towards this person - because he is too young/unaware to use Fi properly, too preoccupied with the situation, too new to this person to display any warmth yet, whatever it be - and a person who expects at least some rapport - be it coz it is a group setting, or a personal setting. Business is often the dominion of Te and there this kind of interaction usually works better as the hierarchy isn't established by group or personal connections; it's established by the position you hold in the company (though even there you can encounter the problem with colleagues in a more informal setting, like during a lunch break).