To clarify, it's not the temperature unit per se, that's just the visible (and common) manifestation of the underlying problem - a website that ostensibly supports an international audience, with geo-location and a dozen language options, gets the basics of i18n wrong. Other examples I've seen are automatically switching to the wrong currency or having wrong translations that are obviously automatic.

I have no problem with websites that are clearly aimed at users from a specific country, which is often the US. That's fine. But things like this really erode my trust in a site, in my mind it creates a suspicion - if you explicitly show me you can provide services in my country and then get the basics about my country wrong, how can I trust your service works properly here?

I was once turned down for a position because (I later learned) my last name is also often used as a first name. The quote was "you can't trust someone with two first names".

Those two guys are just spouting boomer nonsense better left in the 50s, whereas this is "you didn't take 30 seconds to test manually, or 3 minutes to write an automated test for this extremely common and predictable thing."

Not exactly comparable.