durhamjen, you wrote "those who voted to leave",rather than "some of those who voted to leave",so maybe just a slip up.
My ex neighbour is racist and she voted to remain.
She ignored my lovely black neighbours,but was happy with her white one who drank lager all day and was rowdy.
She is not a nasty person.She has recurrent cancer and still works in her 70,s.
Racists come in all guises,and in varying degrees.
A man may have voted remain if he worked for a French company in the UK,but he may not like the French at all.
Some of us will have had experience of seriously anti social neighbours,those people who make life hell for others.The ones who make you nervous in your own garden , blast music through the walls at 3am,and have no respect for others,
I expect those committing these racist insults are of the same ilk .They kick out at others to compensate for their own shortcomings,and will pick on anyone who they see as being weaker than themselves.