I would like to preface this by saying that I'm most definitely not old. I mean, I grew up watching DanTDM, PewDiePie and the like at the later stages of their popularity. You can probably estimate my age given that information, and even I know, understand, and use "lingo" as a word. I understand that it may be an uncommon word to use in sentences purely due to the similarly uncommon topics that it would be used on but it is most definitely not archaic as you both make it out to be. I really don't get why it's so shocking for someone to use it here.
Regarding the cooking slang I was talking about, it wasn't that popular back then so I get that you wouldn't have seen it, but it was definitely used. It's also different from the "let him cook" memes.
