"Post" as a preposition

The rampant misuse of post as a preposition is my pet hate these days. I wonder why it has spread so fast among people who should have known better: the press. What happened to after? If you don't know what I am talking about, take a look at the following sentences:

• Post the match, the crowds were thrilled when SRK did a victory dance on the ground! (The Times of India)
• Post the war, the country witnessed escalated levels of unemployment... (Hindustan Times)
• Director Imtiaz Ali says he is yet to decide on his next film post the success of 'Rockstar'. (Indian Express)
• The ICPA pilots, numbering about 650, have been demanding for long parity in service conditions post the merger of Air India and Indian Airlines... (Asian Age)

In each of these sentences post has been used incorrectly; a preposition like after should have been used instead. But what on earth is a preposition? Macmillan Dictionary describes it as:

A word that usually comes before a noun or a pronoun and shows its relation to another part of the sentence. In the sentences 'I left it on the table' and 'she came out of the house', the words 'on' and 'out of' are prepositions.

 After can be used as a preposition; post cannot. 

 The reason for the confusion is that post does indeed mean after, but only when it is used as a prefix like in the following examples:

• a post-match celebration (not celebration post the match)
• the post-war economy (not the economy post the war)
• a post-dated cheque
• a post-impressionist painting
• post-partum depression
• post-traumatic stress disorder
• post-exercise recovery

So if you too are a victim of this misunderstanding, I hope that post reading this ... er ... after reading this you know how to use post.