This is absolutely untrue, everything has a truth behind it or we would've to cease to exist eons ago. Also, every little incident has a certain fact hiding behind it, even a crack in the floor has some truth behind it. This world is not an illusion, we make it seem to be an illusion.
"I think I am, therefore I am".
The thing you show a good point but the big part about this is that we dont know if this is true to be in theory we dont know if anything exists. Just think about it truth is a illusion in the mind i mean im not even certain that what im saying is "true". Everyone has different beliefs and cultures and what they think i true another person may this is true instead of that an then more people say the same thing. Another example of this is in the medieval time period most of everyone thought the world was flat and that was truth, but now everyone thinks the world is round because we went in space now thats truth in society today and you might say in the medieval ages they didnt know and yeah they didnt what if now we go into another point of view and then everyone believes the world is a triangle or a cube or something like that. Also with religious beliefs how do we know that Hindu gods are real or the greek gods mainly because normally people think different from other people what if im thinking right now that our gods are goats or the world is made out of jelly. Just what if this what if that, i have said this a lot but we dont know and what if everyone has their own ideas that this is true and this is true but deep in their minds they dont know. What is reality and will we ever find out we dont know.