What does squealer walking on his hind legs show?
When Squealer gets up and walks around on his hind legs (carrying a whip, no less) he is showing that the revolution has completely sold out. He is showing that the pigs are no different from the humans that they overthrew at the beginning of the book.
At the beginning of the book, everything human was bad. The pigs even had to explain how birds could still be good even though they walked on two legs. Now, a pig (which is not even supposed to walk on two legs) is walking around just like a human.
So the true nature of the pigs in this book has been shown -- they are oppressors just like the humans were.
It shows that the Pigs were no different to the humans. It also shows how Old Major's speech went in vain, it may also show that Old Major just wanted the pigs to be in charge all along.
when squealer walks on his hind it shows how the Mr Jones and the pigs were no different. it shows how old majors speech went in vain. the pigs were the same as Mr Jones.