[Re. men putting their arm around women's shoulders]
Trust me, it's an annoying form of territorial pissing.
I, and many others, don't trust you. If you think it is always "territorial pissing" then you're miserable and misanthropic. The people viewing it always as such are the ones doing the territorial pissing - feminists marking other women, and how and what they think, as their territory.
You can't speak for all the men who do it, nor the women who they have their arms around. As is obvious from the comments, plenty of men do it affectionately, and many women like it.