Yes, any admin has the capacity to delete a thread and/or a post.
It is, however, something not done lightly.
So far, my score has been...
A dozen or so 'double posts' that were errors of tremulous fingers [or something]..
And a thread which included a warez link in the lead post which necessitated the full thread's removal....[ it had about 2 respondents who essentially were wishing the thread author a fond farewell].
There are reasonable standards and codes of conduct that 'should' be followed on a public access site such as this which require dilligence of supervision.
DeviantArt, for example prided itself on being very open and liberal...anything goes......trouble was, anything/everything came.
Now, they, too have found it necessary to cap the exuberance of youth just a little...and the 'closing' of threads from further comment is one 'good way'[tm]....