These conflicting messages from Google are very confusing!
In that case, Google Webmaster tools is not actually reporting an error. That's a report to show you what URLs Google tried to crawl but couldn't (due to being blocked) so you can review it and ensure that you are not accidentally blocking URLs that you want to have indexed.
I agree that it's confusing in that the report is in the "crawl errors" section.
(I built Google webmaster tools so this confusion is entirely my fault; but I don't work at Google anymore so sadly I can't fix this.)
So a couple of questions: - What is of value for a user? - Who is determining the value for the users in these cases?
As always, it's not always quite clear on what treatment you should use for search pages!
In any case, I agree with you, search engine indexing search results would be bad, but the line is not that clear all the time!
Some vertical search engine result pages are a great and relevant result from a user perspective on the question they are trying to solve.
Also if you have some kind of recent searches list and those link.