The world is full of people - each with his or her own social habits.
How public and political figures behave in groups of people varies, too. How we react to their behavior depends, in part, on our own social habits.
In my previous marriage, my then wife had lots of friends I didn't know. She was involved in the arts community far more than I was. So, she had close friends I had never met. I only met them from time to time when I attended some function or another.
At an art exhibit where some of those friends were showing their work, I met some of those friends. One, in particular, a woman about the same age as we were, came up to me, wrapped her arms around me, and gave me a big, wet, sloppy kiss. Alcohol was not involved. While I'm not a person who objects to hugs and the like, I felt a little uncomfortable with this display of whatever it was from someone I had never met before. Beyond that, I was concerned about my wife's reaction, since she was standing right there.
So, I asked my then wife about it after we left the exhibit. She said, "Oh that's just Donna. She does that to everyone, pretty much." So, OK. The next time I ran into her, she did it again, but this time I didn't feel that uncomfortable. It was her habit to greet people that way. So, OK. No big deal. I like kissing. But, the first time, it was very disconcerting and uncomfortable on several levels.
The takeaway is that different people do different things. Sometimes, people are more demonstrative and physical than is comfortable to others. That's how they are. Once you know that, you can see what might be uncomfortable in a particular circumstance as normal behavior by that person, and just go with it.
On the other hand, if you truly do not like physical contact with people you don't know well, it can be very difficult to adjust to a physically demonstrative person. Then, avoidance of that person is probably the best approach. Still, it is the intent on the person's part that should be how you judge their behavior, whether you are comfortable with it or not.