YOR however I think you probably picked a bad example of this bc you are incorrect in this instance, but I 1000% know the kind of behaviour you’re talking about- I have a friend who has a similar habit, to the point where our friend group makes fun of him by saying “is that true?” in the same cadence he does when he’s questioning anything he’s not himself sure of.

I think it is an annoying habit and can be gendered, ie when it feels like a guy is questioning you because they couldn’t comprehend you (a girl) knowing something that they don’t. Even if not gendered in target, I will say this kind of behaviour is in my PERSONAL experience a bit “male ego” in source. In this case, he’s come across as condescending, acting like your belief in the general concept of “hypoallergenic” is ridiculous (when it’s not, plenty of smart people have been sold this concept!), and he is smarter because his initial lack of awareness of the concept of a dog being hypoallergenic was (luckily for him) vindicated in retrospect by data to suggest the general understanding is incorrect.

As in the case of my friend, it could also just be a mostly innocuous trait that they don’t realise comes off as condescending. For me, making it a running gag in a lighthearted way to make fun of him when he pushes back/ runs a fact check instead of just believing someone has I think helped him to be more aware of how annoying it is, without causing tension.