“All is illusion,” “Reality is a product of the mind,” “Objects never exist independent of consciousness,” and so on are, quite literally, the definition of gaslighting. These positions are foundational to almost all schools of Buddhism, and the only school that doesn’t play this game with people is Classical Theravada. CT is the only school existing today, other than some rare exceptions, that teaches people that reality does exist, and starts from there, and then teaches people how reality exists. Though, just to be clear, I don’t know of any other schools that exist today which don’t gaslight like this, I’m just covering my bases. The suttas themselves, of course, support the CT position, and so surely many who read them, but are unaffiliated with CT, have the right idea, too.
These other schools are even more insidious and malevolent when we understand that their positions aren’t actually even coherent. If objective reality doesn’t exist independent of mind, then the teachings themselves wouldn’t exist outside the adherent’s mind. This would mean that the teachings couldn’t possibly by true, nor could anything else! Not to mention the myriad other logical issues with such ideas. Thus, these schools prey on people who have issues with learning, logic, and understanding basic ideas and thinking. In other words, they are gaslighting vulnerable people:
gaslighting, an elaborate and insidious technique of deception and psychological manipulation, usually practiced by a single deceiver, or “gaslighter,” on a single victim over an extended period. Its effect is to gradually undermine the victim’s confidence in his own ability to distinguish truth from falsehood, right from wrong, or reality from appearance, thereby rendering him pathologically dependent on the gaslighter in his thinking or feelings.
The origins of gaslighting are colorful: the term comes from the title of a 1938 play and the movies based on that play, the plots of which involve a man attempting to make his wife believe that she is going insane. His mysterious activities in the attic cause the house’s gas lights to dim, but he insists to his wife that the lights are not dimming and that she can’t trust her own perceptions.
When gaslighting was first used in the mid-20th century, it referred to a kind of deception like that in the plots mentioned above (sense 1). In the current century, the word has come to refer also to something simpler and broader: “the act or practice of grossly misleading someone, especially for a personal advantage”
Do I sound harsh? Well, sorry, but telling people that reality is imaginary, and everything they know is wrong is really a very evil thing to do. Markedly so, when we notice this only ever is effective on people who are simple thinkers, and can’t see the flaws in these positions. Gaslighting is evil, plain and simple.
On the other hand, telling people that everything they know is real, as while it may be largely pannatti, it is founded upon what is ultimately real, but that there are things that are deeper than they know, and beyond what they normally perceive, and how to practice to see the fundamentals of reality is what arahants do.
Classical Theravada is the only valid system of Buddhism (except for some hypothetical schools that I am unaware of).