"Why do the men who are MGTOW hate women?"
I don't think they genuinely do hate women...they just believe no good can come from a man who devotes so much of his life to women.
Some of the more ideologically driven MGTOWs may have some very harsh observations they make about women...but it's no harsher in my experience than the observations that many feminists make about men.
"What is the purpose of their movement and what are they trying to achieve?"
Frankly, I think what they're trying to achieve is living a life on their own terms, and educating the general public that they are nothing like the pre-existing prejudices that people tend to harbor towards men who are not attached to women.
"A bunch of whiny blah, blah, blah, blah, blah..."
Actually I think most MGTOWs are still sexually active...they just are sexually active with women who understand that there is no chance they will ever hold a position of influence over them.
Furthermore what I find funny is...'men going their own way' is so "laughable" that there is no shortage of people like you who toss around the shaming language. I think what you need to understand is...most of them have invariably outgrown such petty childishness...hence their willingness to identify with the moniker in spite of the cliché reactions of people like you 'Anonymous.' ROFL!!!