Notice I didn't use the word lie or liar, because the traditional definitions require intent to deceive. We rarely have access to each other's true intentions, so I don't think it is a useful term to use in these discussions.
What I believe is that we shouldn't be afraid of calling out people who casually spout easily disproven bullshit to make their argument. Saying you can only call out someone for being wrong doesn't go far enough. OP was arguing the position that there is too much connected tech, so much that in the future we may not even be able to buy a non-connected toothbrush in the future. I'm also IoT-skeptical, as many HNers are. It's a popular position that we don't want a world where IoT is mandatory. But as evidence, they gave an anecdote about shopping for a bathroom scale. I tried to be intellectually charitable to that position and assume good faith, but it didn't hold up without devolving into absurdity.
That's why I didn't say their anecdote was a lie. I can entertain the logical possibility that someone who sincerely does not want to buy a connected household appliance can go shopping for one and have difficulty finding one to buy. But it just doesn't play out, especially for someone who is on a specialist tech forum like HN and has clearly skeptical views on IoT. I said you have to work really hard to put yourself in a position where you can go shopping for such a scale, but face such difficulty that it took "far too long" to find one that is not "demanding I connect it to the Wi-Fi and download a smartphone app."
If you wanted to make a video of yourself not being able to buy a dumb scale, you could go to an tech-heavy electronics retailer that also sells appliances (like Best Buy, Microcenter) or a boutique high-tech gadgets store (like Sharper Image or Brookstone) and only find connected bathroom scales. I just checked what is in stock in a San Francisco Best Buy and the only scale is an IoT connected on. But that would be twisting the truth, because who in their right mind would check only Best Buy in order to buy a dumb scale. it takes a couple minutes on major retailers websites (Target, Walmart, Home Depot) to show that even if you limit to items in stock in tech-heavy places like San Francisco (if there is a place where retailers might assume their customers don't want dumb scales, it's SF), the first and usually cheapest options are dumb scales.
So let's Occam's Razor this. What is more likely? An IoT-skeptical HN poster actually went out to buy a non-connected bathroom scale and genuinely struggled to do so? Or an IoT-skeptical HN poster had to click or sort through a few different options and actually read product descriptions, then exaggerated this anecdote (or totally fabricated it) to advance their position?
But does that even matter? If they aren't a liar, then they are at best intellectually dishonest, and at worst intellectually incompetent. We don't have access to their mind and so can never know which of these three they are. No matter which of these three they are, any of them is a reason to invalidate their argument and call out their anecdote.