Former England defender and Salford City co-owner Gary Neville recently criticised the "negative" display of the St George's flag and said he had ordered the removal of a flag from a building site that he invests in.
Salford City's League Two fixture against Oldham Athletic was delayed later that week when two pitch invaders attempted to place a St George's flag inside the centre circle at the Peninsula Stadium.
Far-right group Britain First claimed responsibility for the incident, saying they "teamed up with local Salford patriots" to protest against the "treachery of Gary Neville".
"At any time in history there will always be some disunity under the surface," said Southgate.
"Life is economically tough for a lot of people so I understand why people are disaffected.
"Covid [the pandemic] was a good example where people did shopping for their neighbours, they rallied round one another, that's what British spirit is about."
