My problem with the left isn't generally with the causes they promote or the social positives they latch on to - generally the left hasn't been all that bad at actually identifying problems, with a few glaring exceptions (rape culture or the effects of atmospheric lead pollution on crime anyone). Environmentalism is good, reducing pollution is good, increasing worker safety, building the middle class, strong social safety nets, these are all fine ends to work towards.
No, my problem with the left is that their proposed solutions are generally tipping the hat to if not being completely glued at the hip to bizarre socioeconomic theories that matured and should have expired in the 19th century, often revolving around pseudoscientific or completely invented social dynamics. Coupled with Alinskyite tactics and still drawing to an extent on cold war era agendas, the left is often more problematic than the right - which in modern political parlance translates to anyone who disapproves of the abovementioned package.
I would hope that with the dawn of the information age as embodied by the internet and the growing awareness it brings to people, we can finally begin to move past these sickly old manifestos and failed cultural experiments and move on to something more practical - not just evidence, but evidence based solutions. If something is working, leave it alone unless a clear improvement can be demonstrated. If there are problems let's not pick our Emmanuel Goldstein du jour and try to somehow work the solution into an attack on that group as demanded by the dualism that is leftism. Let's work out the best way to deal with each situation on a case by case basis.
As should be clear from the above I'm neither a leftist nor a conservative, I'm just one of a growing groundswell of people who are rapidly getting tired of the received wisdom of noisy polemicists, and not in a way that's going to lead to a communist revolution either.