Most people usually see common scammers writing emails with no capitalization to scam their victims, especially if it is not their first language.

More importantly, tech literate folks in here are tuned to ignore such writing styles as they can figure out writing styles that are from scammers, LLMs and impersonators from dodgy domains.

So, you’re right to question this and I find this trend immature and I assume anyone using it to be in the realm of satire and of unserious character.