interesting that chabad websites are blocked...
i dont think anything is "blocked" it just searches specific websites that the creator asks it to
Perhaps the creator should add a feature where you can see which sites are searched and suggest additional sites for inclusion.
I did mention to him to show which sites, also I was just thinking maybe a way to "select which sites" you want to search from his list.
He can generate a custom generate query based on which options are chosen.
I assume he hosting isnt the search appliance. Hes using Google CSE site search which lets you filter the results which Google will dump in a iframe. Not to belittle his his work but it takes 5 mins to put together that site.