I think one confusion here is the difference between word search and using filters. The word search in the green box looks for the word in the recipe title, book title, author name or ingredients. It is not looking for the word in the filter category tags. If you are searching by Indian in word search you are seeing recipes with Indian in the recipe name, book title or with ingredients with Indian in the name. That is not the same as applying the Indian filter tag, which gives every recipe that is Indian in origin and has had the tag applied by our indexers. The same applies to Italian. So when looking for recipes with an ethnicity it is much better to use filters.
But that doesn't help your particular request as filters are AND not OR - if you enter more than one filter you see recipes that contain both filters not either filter. The Boolean word search using OR should resolve that (though as I explained above it's not a good search for ethnicity) but it doesn't seem to be working so I will get our developers to take a look.