Those buttons are added by JomSocial itself when you have the JFBConnect integration setting enabled. To remove, you'd need to modify the following file:
/components/com_community/templates/default/register.index.php
Around line 116, you'll see:
<?php if ( $fbHtml ) { ?>
<div class="auth-facebook">
<?php echo $fbHtml;?>
</div>
<?php } ?>Remove that code and the buttons will no longer display.
I hope that helps,
Alex
Social login buttons on Jomsocial registration
