The whole thing is an absolute non-story.
A local Police Authority (Croydon) sent out some recommendations to publicans of how to prevent trouble seen in previous years following international tournaments - including having door staff on duty, only using plastic cups, and barring football shirts. That's just it: suggestions, and not even a specific mention of England shirts, just football shirts. Between the Sun, it's mouth breathing readership and well reasoned and thoroughly researched internet posts it turns into "immigrants/the PC brigade/whoever try to ban England shirts".
****, it's not even bad advice. If I was watching a match at a pub in Durham, England were going out, everyone had been drinking and the mood was getting ugly, I wouldn't want to be sat between a big crowd of Toon supporters and big crowd of Mackem supporters.
In short it has nothing to do with lefties, Muslims, immigrants, homosexuals or whoever else you want to blame. The only people to blame are the minority of football supporters who can't handle their drink and can't enjoy a match without trying to glass some poor sod.