Yes however I doubt the author was an IRC user. For chats people generay do use lowercase cause it's easier but this article is also about using lowercase outside of chats.

This user I think got it from Tumblr (firmly millennial).

Gen Z I would think default to title case because that’s what smart phones produce when not wrangled.

No they disable auto capitalization explicitly in their keyboards.

That depended on your IRC server of choice.

I grew up on some where you got flamed very quickly if you didn’t clean that up (e.g Espernet).