it'5 l1k3 th3 01d d4y5 4g41n!

Nah, I'm with OP, it annoys me every damn time. but to each their own.

The only linguistic argument I'll accept is that using it amongst fluent speakers doesn't cause linguistic arguments.

it was completely not a valid argument, but it made a point. Throrns throw the same kind of pretentio🅄s shade in my mind as the leet speakers in the 90's and 00's. People can obviously read either, but it's more of a look what I can do and let's bring this old thing back without addressing that we got rid of it all on purpose.

edit: Thanks for wiping that off @dream_weasel