I think you're extrapolating further than I intended.
I used the phrases 'low-skill-low-virtue underclass', 'slice' &'subgroup' for reasons of being precise, not as dog-whistles.
'Subgroup and slice' because Canada definitely imports some elite human capital from India. Those numbers haven't changed over the last decade. It's the 2nd type of immigration that's exploded and is worth talking about.
As for your implication, I didn't call them Sikh because they aren't all or even majority Sikh. For the ones that are Sikh, their religion has very little to do with being low-skill or low-virtue. They're low skill as a matter of fact. A person doesn't chose to move to a bogus diploma-mill without basic competence in English, if they had meaningful skills. Low virtue because it involves actively abusing Canada's immigration system and closes your door to most respectful careers. It isn't endemic to the religion or the people. It is endemic to post-1980s Punjab. Now yes, being Sikh does make them more susceptible to being drawn into gangs once they're in Canada. But, there are enough non-Sikh gangs for the rest of them as well.
If your sieve preserves pebbles, then you'll get pebbles. Canada created a system that actively imports 'low-optimism, low-skill & young Indians; with no opportunities back home; low attachment to the homeland, and a propensity for using shady methods for immigration'. Smart Sikhs & Indians alike are staying back home or working in the US, where wages and opportunities are plentiful. There is ofc the aforementioned steady stream of high-skill Indians moving to Canada, but their numbers have been outstripped over the last decade.
If Canada had focused on expanding their high-skill pool while stamping some unsavory backdoor loopholes, then they could've had an excellent decade of productive immigration. Instead, they laid a red-carpet by the backdoor, added a 8 lane highway and now it's getting overwhelmed by unsavory backdoor users.
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I acknowledge that low-virtue might not be the best way to phrase it. It's just that this group is desperate for survival. They have no time or concern for integration, Canadian culture or the west's conception of civic sense. While it manifests as low-virtue optics, it is primarily about individuals who refuse to give up extractive 3rd-world-surivivalist zero-sum mentalities.