This is only an issue if you study the secrets from a physical understanding. Studying the secrets from a spiritual understanding will allow you to die to yourself (ego), or the world may view you as a madman, meaning you find joy in the stuggles of life, you seem happy when the rest of the world would be mad, or vis versa (Hosea 9:7), and this is because you live more in the spiritual world than you do in the phsyical world. To the religius community you may appear to have fallin into apostasy, as you exchanged it for spirituality. The things of this (physical) world are of an infinitesimal value, but the things of the spiritual world are of an infinite value, and so we mainly concern ourselves with spiritual matters.

No, anyone can study the wisdom of Kabbalah, these are just traditional rules that make it ideal to study the wisdom of Kabbalah based on the life experience they provide. But these rules are meant to be interpreted spiritual and not physically, meaning a man (of the spirit) is not necessarily a physical man having the gender of male, but a male is a giver whereas a female is a reciever. A person who is physical a female could very well be a spiritual male (a giver). Jews are those who wish to unit in unity, creating a spiritial connection to one another as the word Jew who are from the tribe of Judah/Yudah (Yehudi) and Unity (Yechudi) have an almost identical spelling. Being over 40 is anyone who has obtained the emotional, psychological, or mental maturity of a "40 year old". You may only be 12, yet you are an old-soul, or you may be 55 but still act like you're in highschool. Marriage is not corporeal love to another humanbeing, but being in an intimite, personal, relationship with the Creator. These are the people who should study the wisdom of Kabbalah.

Kabbalah is the essence of the Judism and Christianity, and really all religions. You are just studying their source. You will find that as long as you interpret the Kabbalah spiritually and not physically, it doesn't go against any the major religions teach. Each religion has a rest of rules or doctrine it follows. The spiritual understanding of each of these laws are contained within the physical laws, they are the essence or spirit within them. By understanding and following the spiritual laws you will automatically be follow the physical laws. This is why Jesus simplified the 10 Commandments into simply loving God and loving your neighbor as yourself, (which can even be simplified further). By simply loving God and your fellow humanbeings you will be compelled not to break the physical understanding of these laws either.

There is only one way to know if the secrets of Torah are true, and that is to test them yourself. We do not believe what anyone tells us about spiriutality, but we strive to have a direct experience of it so that we can know if it is ture. Ultimately only you can know if something is true or not. We do not wish to be known as "believers" meaning a person who takes what they hears from someone they consider to be an authority or who they believe has their best interest at heart. That person could also be wrong and they are simply stating what they also believe is true without have a direct experience of it themselves to know for sure. Believers are those who blindly follow the religius leaders of this world, who likely also blindly followed their own leader before them.