Why would a speaker choose to not release the transcript to a speech?
Why would a speaker choose to not release the transcript to a speech given in a university forum? If you mean an outside speaker who was hired to give an invited talk of some kind? And perhaps paid for speaking? The speakers contract with the university may prohibit circulating or providing a transcript and/or audio/video recording. It is quite likely the speech may be used at least in part in a forthcoming book. In fact some books are basically the transcripts of speeches. Or rather, speeches are based on essays-in-progress, which are finalized based on questions and comments from speeches. Thus such speakers dont want to share the transcripts.