I have seen that whenever you want only Twitter and Facebook enabled from Sociable list of networks, it actually loads all other networks within the html code, but marks them display:none;
The solution to remove them completely:
Take out all networks that you dont want from the arrays - remove their respective codes. After that, you need to reset the plugin, as it keeps the info in dB as well.
Be careful not to make any mistakes while you are removing, always make a backup of your original php files. Before you reset the plugin, refresh your website so that you know that the PHP code is working and you arent missing any ),} in your code :)
You can always find whereabouts of the code in files by using
grep -nr "Twitter"
Perhaps you can remove also any extra loaded js files...
in sociable.php look for $sociable_taxonomies
delete all three lines with .js