Well, actually, Thatcherism was not all bad. She did have her good sides: she destroyed the extreme trade unions, which had long lost sight of their purpose, and had turned into a cancerous growth that strangled the country. She gave Britain a new sense of moving forward. She got the finances in order. And she had the guts to stand up against the Warsaw Pact for, as it were, western values, in times when few in Europe were willing to. Also, she, as a person, was definitely not of the worst sort you see as a politician. As in: she took no bribes anyone was ever aware of, and was, at least on a personal basis, fairly honest.
However, as Tyrion Lannister so famously said in GoT, nothing before the "but" in a sentence counts. :-)
Even after taking all the undoubted merits of her tenure as prime minister into account, I still think she did more damage to the fabric of British society, than good. The main areas in which the Thatcher era was, especially in hindsight, disastrous are the following:
- It is all good and fine to shaft the kind of parasitic "caveman commie" trade unions she was dealing with. Shaft them well and thoroughly. That much was good conservative instinct, and good politics. But a truly great politician would have realised you have to put something else in their place afterwards, lest even worse stuff will fill the void in the medium term. But nothing was done, and labour relations, and with them the gaps between the classes, have grown alarmingly worse ever since. Amongst many other institutions, a functioning market based society needs something like trade unions, like it or not. If not in name, but in function. Basically destroying them was a very short-sighted and petty-minded victory.
- Overall, she was (and due to financial constraints, up to a point had to be) hell-bent on undoing a lot of the institutions aimed at increasing social cohesion which had been introduced over the previous decades. Such as the school system, which was much, much better when I was a kid, than it ever was afterwards. And arguably, the terminal decline of the state run school system started in the Thatcher years, during which everything that cost the government money was seen as an unnecessary expense. Even if in the long run incurring said expenses maid perfect sense - schools are a prime example of such an expense. But during the Thatcher years, the pendulum swung too far back. After excesses of state regulation, nanny state antics, and wasteful spending (there is a reason the movie "Brazil" was done in Britain, of all places), suddenly lots of sensible things were also thrown out of the window, along with the bad stuff. Perhaps inevitable in such circumstances, but still extremely damaging. Especially as few since then have really tried to repair this damage.
- Her tenure saw the birth of the modern financial sector in Britain, which has turned out to be a much worse cancer on society at large than any leftist structures could ever have been. And I'm saying this as a fairly conservative person who is not against banking, or even the financial industry per se. Far from it. But the anti-social, uncontrollable monster that is now the City was hatched in the "bugger thy neighbour, if there is profit in it" and "greed is good" era of Thatcherism, and has grown ever since.
- She herself was a more or less decent person, but the majority of chaps who got to power in her wake were not. Amoral, greedy little persons, to an alarming extent. Since she was boss at the time, I hold her at least partially responsible for this.
- And there is also something she is personally responsible for, with her jingoistic attitude towards all the other components of the UK - in particular, the Scots. When I was a kid (and I am Scottish), being pro-independence in Scotland was a quaint notion held by some university types. The high-handed and arrogant manner in which Thatcher in particular dealt with the early stages of the devolution process did a lot of damage to the Union, and to the idea of getting along within the UK. In terms of politicians being sensible in this regard, it did not get much better after her, of course. But at least in the timeframe after the war, she was the first prime minister who openly showed an active dislike for Scotland, and Scottish affairs. She let her personal feelings get the better of her, and this was absolutely not what was needed at the time.
I could go on, but these are some starting points, if you want to continue the discussion. :-)