The answer is simple, almost evident in the question. Here's why:
zsh is not
bash, it is a different shell.
zsh will not use the default files built for
.bash_profile. These two files are startup configuration files for
zsh has its own startup configuration files.
You can find out more about them here on the
zsh intro page:
There are five startup files that zsh will read commands from:
You had mentioned your aliases don't work, to fix this, apply your aliases here like so:
alias sz='source ~/.zshrc' # Easily source your ~/.zshrc file.
alias ls='pwd; ls --color' # Alias 'ls' to: pwd + ls + color.