Why? Out of pique? Out of being disrespected? Out of a general tit for tat?
I don't agree with the UK voters today (from my safe spot of not being a UK voter) but it seems pretty silly for the EU or countries within the EU to treat this vote--assuming it goes ahead--as a petulant child would, damn the consequences. They should and probably will make a rational response based on their own interests whether or not they're "annoyed" or whatever the word is with the UK.