why do girls type in lowercase like this?

[Lorence]

why do they type like this?

 

[Sandriguez]

why do they type like this?

to express their passivity over text

 

[JohnDoe]

It's a power move, they're trying to show that they don't care and are in charge. By doing it, they're implying they are the top dog in the conversation and you are beneathe them.