So you should know that not many people outside of the incelsphere use the word 'normie' unironically anymore. Lots of other groups used to, me being a part of several, and we stopped using it to avoid association a few years back but the chantards were being so loud with it that no one noticed really.

A lot of language works like that, when you see despicable people using a phrase that you commonly use, you generally tend to stop using them. Which is why there are things like corporate slogans and bumper stickers. All branding and identity.

So people self-segregate their language by creating new in-group words and retiring common definitions and whether or not they adopt out-group slang. This creates a unique fingerprint that, if a user is mostly exclusive to that slang group, they will treat the slang as common parlance and unconsciously slip into it when interacting with out-groups.

For example, when Digg died, it was common for redditors to call out the immigrating users for their particular line spacing which wasn't really used on reddit at the time. Same language, slightly different slang, but fundamentally different message structure.

4chan's 2016 crowd were super adept at sniffing out incoming redditors to a degree that almost makes me envious.

So when someone uses the phrase 'normie' like that, they are very likely to have spent most of their social upbringing (when linguistic adoption is still plastic) on chan-adjacent incel boards.