Configurable GitHub default merge action: merge, squash, rebase

I don't understand how this hasn't gotten more attention throughout the years. I would like to learn about why that is.

I am a big fan of Squash and Merge but it's saddening that users have to configure that by hand on a repo when they first merge a commit via the GitHub UI, as many people aren't aware or don't think about it which can lead to nasty commit histories.

Am I missing something? Am I git'ing wrong?