What profiles (Shell init scripts) are parsed on process spawn depends on your shell. This is the documentation man page for bash. There are two different sets of scrips sourceed depending on if the shell is spawned with --login or without.
bash --login
it first reads and executes commands from the file /etc/profile, if that file exists. After reading that file, it looks for ~/.bash_profile, ~/.bash_login, and ~/.profile, in that order
bash
When an interactive shell that is not a login shell is started, bash reads and executes commands from /etc/bash.bashrc and ~/.bashrc
note
The only impact the very weird --login flag has, is the init script file location. If you configure your system, just do ~/.profile and make ~/.bashrc symlink to it.