Because frequently Easter eggs are frowned upon at large companies and I suppose developers may still be trying to sneak them in by obfuscation. So this linter is trying to catch those cases
Historically, Easter eggs were implemented as a way of having a verifiable resume. To reduce employee bargaining power, companies didn't include developer names in software credits. So even if you worked on project X, even if you designed and wrote the entire program as was common at the time, the developer didn't have any proof they could use on their resume. But, if you sneak in an Easter Egg, especially one that displays your name, you could use that as proof.
So, given the antagonistic relationship in which Easter Eggs originated, I'm not surprised that large companies would continue that antagonistic relationship.
I stuck difficult-to-find easter eggs in my game cartridges precisely because I wanted to prove that I'd written them. The eggs are not spectacular, nor do they subtract from the player experience. It was just signing my name, when I wasn't allowed to.
In Japan, game companies forbade programmers from putting their real names in their games. It was an anti-poaching move, the studios didn't want their programmers hired out from under them.
So the game programmers put aliases in instead. Hence why you see such strange names in games like Yu2, Nakazoo, Faw, S.Miyahon (who is actually Shigeru Miyamoto), etc.
Your source points out while the term "Easter egg" was coined to describe a circumstance you mentioned, the concept is older, and used for circumstances other than what you described.
Realistically this would be the best way to get your easter egg caught.
Unicode escape characters in comments will draw most people's eyes immediately, it just doesn't look natural.
Instead write the easter egg in completely plain sight attached to a boring change, make sure the PR is passing CI on the first try, and a reviewer will skim for exactly .5 seconds before replying "LGTM!".
