It's things like this that give campaigns bad names. Following on from TS earlier post, it just shows how infantile things have become. It's not an argument, and it is absolutely untrue.
It is precisely because it is damaging to our international (non-EU) ambitions and our engagement with the wider world that we need to leave the EU. The EU's customs union and regulationism frustrates trade with markets external to the EU and the glacial pace of its sclerotic bureaucracy in negotiating anything (other than more perks for themselves) makes us miss opportunity.
In regards to immigration, which is what I think is behind this type of thing, the UK has an excellent record of taking in and integrating all sorts of people from all sorts of places.
It reveals more about the mindset of its creator than anything.