Its wrong to send people to prison for council tax defaults!...so why there a stautute that permits it?

I was born in the nineties so i grew up around alot of denim, the spice girls, those gooey alien toys and stories about how bad Thatcher was by introducing poll tax. Statistics show that in 1993, 1361 people were imprisoned due to a poll tax payment defaults. However, that was almost nine years ago, so i would not blame if you get a sense of shock at the read of my next sentence. In R (on application of Amamnda Aldous v Magistrates Court 2011, a women was sent to prison for not paying £7000 in council tax.
But were the magistrates being to harsh? £7000 is a alot of money and if the law is not completely strict enough then people will feel that they do not have to pay their taxes at all.