First thing's first: did you restart Vim after altering your
.vimrc? Unless you
:source it manually or have autocommands set up to automate this when it is changed, it is only read on start-up.
If you remove the configuration from your
.vimrc then it should no longer apply. Most likely some other part of your configuration is affecting these keys.
Try running the following command within Vim to see if your arrow keys are currently mapped, and if so, what mapped them:
:verbose nmap <Up>
If that reports
No mapping found, then something else is going wrong. It's worth checking that Vim is actually receiving the arrow-key events. Try entering insert mode and then pressing the series of keystrokes:
That should tell you the keycode that Vim is receiving when you press an arrow key, and you can then investigate further why that is not resulting in movement for you.