As I said, I would've liked to reword the original to say something along the lines of "Notwithstanding the valid criticisms about their cheating of emissions requirements..." and also clarified that the above experience I had explains why to me it's not surprising that consumers are buying more VWs. Unfortunately, I can't change the post, which is why I had to say it in the reply. The criticisms of VW are valid - their cheating of the emissions requirements is something that should be punished way more than it has been.
I closed out my post with the criticism of the Vauxhall to give contrast to my experience with two contemporary cars. I drive a '98 Camry at home, so I don't have experience with cars younger than ~20 years normally. This gave me a good chance to experience them and it highlighted how different the two vehicles were, especially since they were both hired out by Europcar as the same category of vehicle.
Also please note that I was trying to praise the vehicle, not mate a statement about VW themselves. Per the above, they were wrong for cheating emissions requirements. Regardless of whether it was achieved legitimately or not though, my post was trying to put into words why I find it unsurprising that many people are buying VW vehicles if the Polo was an example of what they're producing.
I said that I'm not sure whether their cheating of emissions is the reason why they can produce a compelling car, not whether it is an 'advantage'. It's undeniably an advantage - if nothing else, cheating on that helps to illegitimately sell cars to people who want 'greener' cars. What I am saying, however, is that I don't know if that translates to their ability to produce an all-round compelling car that appeals to a large market enough to explain significant increases in sales (i.e.: because it is the differentiator between a car with rubbish/good fuel efficiency, or rubbish/good performance). I simply don't know, which is why I said that.
When I post on HN, I consider whether my input could add to the discussion. The article was about VW seeing higher sales volumes than Toyota, yet the discussion was focused purely on their cheating of emissions requirements. I felt my comment could add to the discussion by providing one anecdote about my experience with their car and how, more generally, that might translate to why consumers are buying the vehicles.
The reality is that I can't come show you in person my boarding pass for my holiday there and my booking receipt from hiring the car. I can't show you my employment history or bank accounts showing no financial incentive to say what I said. There's no way I can convince you of any of it unless you decide to convince yourself that I'm not a shill by going through my post history or something, and I suspect you have no desire to do that whatsoever so there's simply nothing I can do short of trying to explain the rationale behind my post as my defence. The reason I'm trying to do that is because, per above, I legitimately try to contribute meaningful input to HN and so being called a lying shill runs counter to that.
edit: For what little it's worth, I didn't downvote you, though I just saw you have been. I think there's a valid place for you having called me out because you've done it fairly respectfully and some level of scepticism is always warranted. Certianly you made me explain myself which helps others who read it gain a better understanding of what I was trying to say (evidently badly) in my OP.