The sad thing is that it works both ways. If a left party in government is improving things but had to do a compromise and therefore couldn't go all the way the far left is also complaining about that.
Compromise with far right positions should never happen, but compromise in itself is not something bad, and imho it's one of the main problems in today's democracy that too many people see it that way.
As with almost all things: it's good to have principles to stand by, but the world is rarely as black and white as it seems to be.