Bismillah ArRahman ArRaheem
Wa-Alaykum As Salaam
Firstly, not every law we have in Islam can be understood with our infinitely tiny intellect relative to the unlimited Wisdom of Allahﷻ. If that is understood, then we can possibly draw some potential reasoning from those rulings.
Statement Allah says in Sura Noor Ayah##02 that whip 100 lashes to those (BOTH sexes) who commits sexual intercourse. Why equal punishment is given to both.
Answer: That is because in the instance of adultery both are consenting sane baligh adults who have chosen to commit adultery.
Statement : but MOST probably women dislikes getting humiliated by men.
Answer: The rulings and Wisdom of Allahﷻ takes in to account how human being beings were created and the judgement depends on both sexes. In this instance, "MOST probably" is only a probability and is not enough to question the Authority of the ruling. Also, remember, this is in regards to consenting adults. So BOTH would have needed to consent to adultery.
Statement : No woman likes to be exploited by men for their own sexual gratification.
Answer: Again this is a general statement. Women need security, and may do so by attracting the male counterpart n various ways to attract the one who will give them the most security. Sometimes to complete that attraction women allow themselves to be exploited. W e can see this in the Western world where women consider minimalist dress as freedom and female nudity a celebration of the women body, where as Islam sees this as exploitation. And also, what goes on at universities and colleges in Western countries is a testament that sometimes women choose to be in that position early on.
Statement : They(female) will rarely plan to be at the recieving end of zina but men does planning & wait for years to do zina with women.
Answer: Again, a very generalized, statement that attacks only one side of the equation. This ruling is not where some one has been forced to do something they do not want to do. It is where both have chosen to commit the sin.
Statement: After zina women go through a lot of pain mentally and may even commit suicide due to getting hurt psychologically.
Answer: You may be referring to rape here?
Question: Now WHY islam doesn't differentiate b/w men and women when it was suggesting the above punishment i.e of 100 lashes for zina doers.
Answer: Given the above statements, it is because in the instance of adultery both are consenting sane baligh adults who have chosen to commit adultery.
Question: My second question is, Allah order us to cut hand/s of the thief regardless of whether he is married or not. Then why restriction of martial status is applied here in Zina case.
Answer: Not every law we have in Islam can be understood with our infinitely tiny intellect relative to the unlimited Wisdom of Allahﷻ. Comparing zina with theft is like comparing bananas and cucumbers.
Question: Why Allah doesn't orders to stone to death whosoever (whether married or unmarried) commits zina?
Answer: Again, being married and unmarried are two different kettles of fish. The one who is married has access to lawful means to fulfill their desires, while the unmarried one does not.
It should also be noted that in order to carry out such rulings for adultery, the conditions are very difficult to achieve. So much so, you need FOUR witnesses to SEE with their OWN eyes (not a camera for example), the entry of the organ in to the other. And there are subsequent consequences for one to make such an allegation with out the ability to bring forth such witnesses, which is beyond the scope of this answer.