It would be lovely to live in a world where we could routinely show each other genuine affection through touch. Unfortunately, we do not yet live there. Right now, we live in a world rife with abuse, harassment, violence and lust for power over others. Unwanted touch plays a big part in that. Everyone is entitled to the sanctity of their own personhood and bodily autonomy. Others do not have the right to access that without our permission. If you have a well established friendship/love relationship with someone, you probably already know how they feel about being spontaneous touched. If you don’t know someone well already, you have to either read their non-verbal cues very well or you have to ask. It’s not difficult. It’s just more vulnerable that some people would like to be. They’d rather assume/take and then get defensive if objections arise.
If you have never had the experience of feeling like you were constantly being told that your body did not belong to you, but was there for the entertainment or enjoyment of other people, this might take some empathy. Try to imagine what that might be, that every time you leave the house other people feel free to comment upon and touch your body without your consent. Most women have experienced that daily from the age of about 10 or 11. How might that experience wound you or inform your life? It’s a big part of this question.