How to remove an action added by a child theme of Genesis

Thanks to Dan that commented with a useful post I found on Google but didn’t read with the required attention, the solution is this:

function my_remove() {
    remove_action( 'genesis_entry_header', 'shq_genestrap_post_meta_categories', 9 );
}
add_action('genesis_entry_header', 'my_remove', 8);

Using priority 9 in add_action() doesn’t work: I had to set a priority lower than the one used to add the action I’m going to remove.

Anyway, I don’t understand why a lower priority works: it seems to be counterintuitive.

About this I opened another question: I don’t understand why I need a lower priority to remove an action with a higher priority to make it work

Anyone willing to reply is welcome!