Internal Search Results Indexing

Hello!

I found blog articles about internal search indexing which say that it should be set up to no-index and Giphy.com gets penalized almost overnight for doing that.

My questions are:
1. Do you think that we shouldn't index internal search results?
2. Why all porn-related searches show internal search then?

1. If you have just a few tens of pages don't index internal searches, as it would only create thin/duplicate content
2. They have tons of pages and chances are that internal search result pagrs will not create that much duplicate content as those search pages will differ from each other. Also chances are that internal search results actually help them index indovidual pages, as they are created at very fast pace and may not be indexed naturally.
3. Why would you report such websites indexing internal search? It's a waste of time. Let them do their work and let google decide if they create too thin content to be penalized...