Exclude category from main loop but display in sidebar [closed]

Question

I successfully use pre_get_posts to exclude two categories from the main loop on the homepage, archive and author page. My problem is that I want to display those categories in the sidebar! Here is the code (functions.php):

function exclude_category_home($query) {
if ($query->is_home && $query->is_main_query() || $query->is_archive || $query->is_author) {
    $query->set('cat', '-3,-41'); 
}
return $query;
}
add_filter('pre_get_posts', 'exclude_category_home');

That doesn't work. Why?

SOLVED:

function manipulation_parse_request() {
    add_action('pre_get_posts', 'manipulation_pre_get_posts');
}
add_action('parse_request', 'manipulation_parse_request');

function manipulation_pre_get_posts($wp_query){
    if ($wp_query->is_home || $query->is_archive || $query->is_author) {
        $wp_query->set('cat', '-3,-41');                
    }
    return $wp_query;
}