On the contrary; social touch, with the ensuing spectrum between "discomfort/aggression/dominance" and "affiliation/friendship/social comfort" is actually found in all social mammals, it has nothing to do with society, gender, sexual undertones or anything human-specific like that! Even domesticated cats http://esr.ibiblio.org/?p=5962 http://esr.ibiblio.org/?p=1771 have a basic, instinct-driven understanding of how the aforementioned spectrum should be carefully negotiated if one is to establish a genuinely-experienced social bond.
I'm sorry but yes, per the above, Biden's "touchy-feely" behavior with strangers has indeed been singularly clueless, even unintentionally creepy and disturbing, in neglecting these obvious facts. Biden is one of the major figures in U.S. politics and obviously socially competent - he has no excuse for this.