I'm not entirely sure what you mean by 'thread,' but I take it you mean questions? The problem is that you have to select a reason to close ('not a real question,' 'off-topic,' 'subjective and argumentative,' etc) in order to be able to click on the 'close' button to use your vote to close.
While that doesn't, necessarily, make it clear to the person that posted the question, I, personally, try to leave reasons as to why I close questions. Other than that the majority decision of the five (or fewer, if a diamond-mod also votes) close voters is displayed when the question is, finally, closed.
Edited with regards to the updated question:
The owner of this question cannot see the reason why his question is being voted to close.
That's obviously an unpleasant situation to be in, and I sympathise with that, but that's also not what your question asked. Or, at least, wasn't my interpretation of what your question asked.
For what it's worth, though, I do partially agree with you, and believe that the owner of a question, and the case of a Community Wiki question everyone, should be able to see some form of a report on the close votes accrued by a question.
But, for the record, I also think that people should leave comments explaining down-votes, and that's not, typically, the behaviour exhibited (at least in the tags I tend to stick to).