There's an old diss where you make fun of someone by saying "year called, they want their style back". This comic is riffing off of that idea by referring to 2001, when the world trade center in New York City was destroyed in a terrorist attack on September 11th
Man, I really never considered this being an “older” brand of humor. This has been in my saved folder for a long time, it’s a lot about the guy’s face and glasses and that he’s using an old phone to call 2001—and that was all on top of the existing joke. I feel old today.
Regular Show used the joke in one of their episodes, referring to the 80s..which itself aired over a decade ago. So yeah, it's pretty much in boomer humor territory now.
Not really. I mean, I get what you maybe meant, but “boomer humor” is a specific type of humor. If anything, it’s millennial humor, which is literally a different generation of humor. But I’m also pretty sure this was made in the last 5 or so years, still making it gen Z humor? I dunno. I find myself asking “is this joke as stupid as it seems, or is there a level I’m not getting” and the answer is always, “no, take it at face value.”
"[year] called" is a common way to mock outdated objects or behaviours. It's usally followed by "...they want their [mocked thing] back". In this case, it's about the clothes of the guy.
The punchline is, instead of mocking him, he's telling him about a major event of 2001 - the 9/11 terrorist attack. It could imply an actual call through time, but that's not important. The comic basically just wants to subvert your expectations and drops something dark instead of the usual punchline.
People say shit like "2001 called" when somebody is wearing something outdated or doing something outdated. The September 11 terrorist attacks happened in 2001.