I suppose it's true that the left-wing equivalent is the Palestinian flag, or the centrist equivalent is the Ukrainian flag, however this usually comes in the form of a sticker or the odd flag flown from a house window here and there, rather than a row of flags hung from every lamp post on a street.

Quantity has quality all of its own. Although many different causes use flags for promotion, the obsession that certain elements of the English right have with the English flag is at a completely different level.