The problem is that MSZP have basically collapsed as an organized entity... iirc polls have them behind or level with Jobbik.
Last Election
Opinion Poll
Yeah, their credibility took a huge hit for obvious reasons. And, for obvious reasons, it's harder for a postcommunist party to recover credibility than a normal social democratic party. So while they don't seem to have fallen any further, discontented voters seem to be moving towards... urgh.
You're saying that saying "We have lied morning, noon, and night" is bad for a party's credibility?