Only people that were believing in them and burnt are the ones openly saying that they are all frauds, and these people that have been burnt are usually not believable because of the fact that they are losers at this game of fraud. Losers tend to have little of no credibility because of the fact that they are losers even though they are the ones in position to have actually seen the truth.
[In any case for actual knowledge of the Ari the Kabbalah institute seems very good. They have a great edition of all the Ari and without pretense of great knowledge of it they study it seriously. It is the best and most honest approach to this that I have seen.]
This should not be construed as a critique on the Holy Torah, not the written Law nor the oral Law. Rather this is a critique on the creeps that pretend to know it an keep it. in so doing the give the Torah and all Jews a bad name. The religious world are more like enemies of the Jewish people and of the Torah than the friends they claim to be.
In fact I think the Oral and Written Law are very important and I think Reb Israel Salanter found the best approach to make this simple and easy--to learn Musar [the Ethics of the Torah.]