This is interesting question. To me this is more of intuition.
When I am looking onto the screen and reading, my cursor is at a specific point. Now, I want to open something.
It would be best to open new file in the 'left' as mostly people read from left-to-right (ltr) direction. And as the buffers reset on splitting, we subconsciously reset our eyes to '...
The answer is in the doc :h 'wrap':
'wrap' boolean (default on)
local to window
The option is local to a window so setting it in your vimrc has no effect to your windows.
You probably want to set the option for a specific file type either in an autocommand :h autocmd
autocmd Filetype markdown set ...