You can read the full statement from WhatDoTheyKnow here.
www.whatdotheyknow.com/blog
They explain why the hashtag was removed.
Considering the request titles, we determined that the inclusion of a campaign hashtag in the title is extraneous to the purpose of requesting information from public bodies and at odds with the sufficiently focused nature of the requests – seeking to bring pressure on public authorities rather than simply focusing on the requirements of a clear request for information.
For the reasons listed above, we have determined that these requests can remain on the site; however, we have removed the extraneous campaign hashtag from the title of each request.