The left have two basic problems:
1. They have a misconstrued view of humanity.
2. They find solutions and then go searching for a problem.
With 1 it is easy enough to understand where they went wrong. In viewing humanity solely from a collectivist viewpoint they missed the importance of the individual, not so much failing to see the wood for the trees as failing to see the trees for the wood. In doing things for the collective it is necessary to compel the individual to act regardless of whether it is in their interest to do so. This skewed viewpoint will, inevitably, lead to authoritarianism because compulsion is the very weft to the warp of socialism.
Point 2 happens because socialists seeing that humanity does not fit their ideal, see problems that need bringing into line with their vision. This take on life shows so many problems that any mechanism of change, however useless or inappropriate, is seized upon and touted round to see whether it is possible to shoehorn the solution into one of the problems. Using it in some way is far more important to them than making sure that it is the right one for the job.
Hence we have ID cards being touted for everything from fraud to scrofula, "Oh, OK it wont work for that but I'm sure it will help endangered bees if we all carry one.". The EU is another example where we have our agent of change, (moving powers from a national to supranational level), and this will cure all ills. No analysis of where each power should be located for the best effect, just wave your magic EU wand and all the little EUfairies will fix everything.
Then, when it has been shown beyond all doubt that their ideology is flawed and they have used solutions that only make problems worse they understandably, (given human nature), get miffed when you point this out to them. Well despite it being human nature to throw a tantrum when things don't go as you hoped it is time for them to grow up, stop sniveling and look at things sensibly.
I hold out little hope that they will though.
Libertarian meat eater, right wing in the sense of conservative with a small c.