Why does the GOP hate Unions?

I don't get it, someone explain to me why the GOP is so opposed to labor unions.  They bill themselves as the party of the middle class don't they?  Aren't labor unions responsible for the 5 day work week?  And the 40 hour work week?  And child labor protections?  And job security?  And safer working conditions?  And pensions?  And competitive pay?   Don't those things benefit the middle class?  Shouldn't those be things to strive for?   If so, why are Republicans so against labor unions?

I'll tell you why, the way I see it there are 2 reasons and neither has to do with helping the middle class.  1) Big business loves cheap labor and GOP are shills for big business.  You know, part of that whole failed trickle down theory, give more to those on top and hope it trickles down to the peons.  How does holding wages and benefits down benefit the middle class though?   2) Labor unions donate significantly more money to Democrats than Republicans and it's not even close.  Think about that for a second, why do you think that would be?  Could it be that Democrats do more to help the middle class, they push for better pay and wages, they push for more worker protections, don't you think they be more receptive to helping unions?  Of course they would be.  Now if the GOP could bust up these unions don't you think that would benefit them (by minimizing their donations to the Democratic party and Democratic candidates)?  

Wake up people, the GOP is not looking out for you, they are looking out for those at the top, stop voting for them already.