It’s a simple concept of controlling the message by discrediting the messenger. Because this 220;mother” has an ax to grind in this case – defending her vic-son at any cost – of course she’s going to call the whole event a hoax.
This relieves the inquiring mind of any further investigation into this very well done psyOp.
As Lenin said, if you want to control the opposition – you must lead it. This is is just another example.