The INTPs I know are manipulative sociopaths.
and the INFPs deny truth and live in a world of lies and denial.
Eh. I see these things as situational personality type adaptations. IOW, given a difficult social situation, then:
INTPs will obfuscate their way around it,
INTJs will charge it head on and bowl it over,
and INFPs will use a little feel-good sleight-of-hand to tiptoe past it.
Each personality type is quite sure that their method of handling the situation causes the least fuss and harm, and each type is a little shocked at how the other types handle the situation. Watching each other deal with the situation, the INFPs accuse INTJs of being bullies, and the INTJs accuse the INFPs of being liars. In turn, INTPs may well come off as manipulators to both the INTJ and INFP.
Or, alternatively, all three personality types can adjust their filters and accept that there's more than one way to skin a cat.
All personality types have their typical shortcuts or nickel-and-dime rip-offs in response to difficult situations, especially when viewed through the filter of another personality type. But assuming that we're talking about average representatives of each type, then these shortcuts or petty rip-offs typically don't rise to the level of criminality or sociopathic deceit.
IOW, if you have an employee of another personality type, then you understand that they have their own way of dealing with certain situations. You adjust your filter in a way that allows you to see their basic honesty and not get too riled that they do things differently from you, and you go ahead and entrust them with the till (until such time as their shortcuts or rip-offs rise to the level of universally-acknowledged untrustworthiness or criminality).
This philosophy may sound too feel-good or wishy-washy for everyone. But I was a sergeant in the Marines for a lot of years. As a sergeant in charge of troops, I couldn't just fire or transfer the troops when they pulled a petty rip-off or didn't do things my way. And their rip-offs usually didn't rise to the level of chargeable crimes. Nor could I run around beating up on them for being bullies and manipulators and liars when I didn't like their methods--after all, I needed them to get the work done around the place. You work with what you've got.
So I learned to adjust my filter to account for the troops and I accepted that there's more than one way to skin a cat. I kept order and maintained discipline by identifying and curbing the worst excesses, and otherwise I gave the troops some leeway and let them use their own initiative as much as possible. After all, I couldn't do all the work all by myself. Ultimately, we all got along just fine and got the job done. Again, you work with what you've got.