Her death is not exactly the drop of a hat - there have been songs written in anticipation of this event. The Brits (and the Irish) don't have to be liberal to hate Thatcher. And they hate her not for a political label, but for what she did with her power.
As konceptual99 said (and it bears repeating):
she ruined the lives of millions of British people. She viewed the suffering of the working class as collateral damage, a necessary side effect of the smashing of the unions and socialist policy in general. Her policies run deep and are in evidence today - once again to the point where those in need are forced to bear the brunt of the pain of financial policies that favour the haves.
There are many places in the UK that will never view Thatcher as anything other than a disaster for them and their community.