ethical querry

Beta 2 used a number for morality. You might have had 0 for morality and you need 70 for Good. Netural is between 69 and 20? The starship 'Good' choice adds just 2 points to your morility.

'how does work the good/evil in the game... after choosing 3 evil choices i became evil and so after that i always choose good choices and never became good or neutral again...'

Most events don't have a very big influence individually, and the evil choices tend to have a larger influence than good ones. I have gone from good to evil and back to neutral.

Evil to good is hard part because only colonization events and one or two of the other planet based events can cause good influences, while a number of other things can push towards evil.

'because some times i've got always the same event : like piracy, i get it 6 time in the early stage of the game so it's unplayable because i didn't have more than starfighters,'

Events are random, determined when you colonize the planet, I think.

In the case of piracy, it's not a planet event, and as such can happen often once certain conditions are met. That specific event is based, in part, on the net trade income of all races, from what I can tell.

Starting at Neutral, I've shifted from Neutral to Evil and back again several times, and occassionally becoming good all in one game.

In a game where Planet Quality is such a key factor one cannot ignore the chance to improve it!