Can Mars become the ideal planet for humans in the future if no criminals, psychopaths, corrupters, religious, etc. individuals are allowed into Mars, only well educated and needed people (all have to go through tests and be observed)?

Essentially you’re asking if large numbers of people lived on Mars, could we make an ideal society. Succinctly put, no, because Mars can never be a livable planet for masses of people.

No atmosphere that would be heavy enough for us to breath could be held on Mars because the gravity of Mars is weak. This would mean a much thicker layer of atmosphere than Earth, yet because of the weak gravity, the atmosphere would simply blow away with solar winds. If anyone ever lived on Mars it would be in enclosed and small spaces capable of protecting the inhabitants from dangerous solar radiation.

Mars is a pipe dream. We may one day put footprints there, like on the moon, just so we can say we did. As far as terraforming is concerned, it isn’t going to be possible.

Our main interest in Mars these days is to discover if there was ever an ocean there (because we don’t really know for sure how our ocean got on Earth) and did it ever support microbial life.

NASA does not want to “infect” Mars with our germs in case it destroys previous native life. Thus no humans in mass numbers and no terraforming.

Worried about death?

In the Bhagavad-Gita, a famous Hindu scripture, Krishna says: “For the soul there is never birth nor death nor, having once been, does he ever cease to be, he is unborn, eternal, ever-existing, undying and primeval. He is not slain when the body is not slain.”

Think about it.