For decent people, it should not matter whether localist radical Edward Leung Tin-kei was born on the mainland or not. His mother was a mainland immigrant who came to the city 24 years ago, after he was born. But given his extreme xenophobic ideology and that of his group Hong Kong Indigenous, he opens himself up to accusations of hypocrisy.

At the weekend, he admitted he was born on the mainland but came to Hong Kong with his mother at a very young age.

His mother worked hard to secure a future for her child. And Leung was obviously a good student, to be admitted to the University of Hong Kong, where he is studying philosophy and politics. The city did not spit in their faces, as localists do on mainland visitors. Instead, it embraced and offered them a chance at a better life that they wouldn’t have on the mainland.

That’s what our city has always about, a great metropolis built on the back of hard-working and entrepreneurial migrants, transients and colonials.

READ MORE: New storm: Hong Kong Indigenous candidate Edward Leung admits he was born on the mainland

Leung has not even graduated and already has a massive political following. In the New Territories East Legco by-election last month, he finished in third place by securing more than 60,000 votes, an impressive feat.

Too bad it was run on a populist platform grounded in hate and resentment against mainlanders and China in general.

His group organised numerous protests last year that singled out those they took to be parallel-goods traders and mainlanders for harassment, and has been accused of inciting the Mong Kok riot.

Given his own mainland background, it’s fair to ask: what happened?

It’s not unusual that for some people desperate for a sense of belonging, they reject or refuse to acknowledge their own past and go so far as to subvert or fight against their own kind.

Some localists have argued they are not haters, but defenders of Hong Kong’s autonomy, culture and values. That is legitimate. But it’s often a fine line between legitimate defence and hateful aggression. Leung’s Hong Kong Indigenous and other, similar radical groups crossed that line long ago.

As Leung’s political career advances, he may want to ponder his own past. He may yet become a decent person and a good politician.