In Islam, a man is not allowed to touch a woman who isn’t his wife or a close family member, such as his mother, daughter, etc. Similarly, a woman cannot touch a man who isn’t her husband or from her close family. God, Glorifed and Exalted, has Infinite Wisdom in everything He commands. However, this should be seen out of respect and should not be perceived as derogatory. It’s not because that man or woman may not be a Muslim, because even if they were Muslims, a Muslim still can’t touch the opposite gender. Allah knows what’s best for us, and He knows that not touching the opposite gender is purer for our hearts. Adultery and fornication are major sins in Islam, but usually, no one is going to have illegal sexual intercourse with someone right away; it all starts with the eyes and the hands, and Islam prevents this right from the start. Even from a man’s perspective, any male who has an ounce of manhood in him would not want anyone touching his wife. A woman would want the same for her husband as well. Islam protects this and doesn’t allow Muslims to touch what’s not theirs.
And Allah knows best.