Why isn’t bash reading my `~/.profile`?

It has been eons since I had to set up a dev environment and I do need to run some python (CSVkit, specifically).

My default .profile definitely adds my private bin to my path:

# set PATH so it includes user's private bin if it exists
if [ -d "$HOME/bin" ] ; then
    PATH="$HOME/bin:$PATH"
fi

But when I do printenv PATH it is not there. If I run source ~/.profile it does get added to my PATH.

I don’t have a .bash_login or .bash_profile set up, so why would bash not read my local .profile?