PGM seems to me harder than neural nets, but the trend in the last couple of years is to include probabilities in neural nets, so they're hot.
[0] https://www.amazon.com/Probabilistic-Graphical-Models-Princi...
I sort of see what you mean since NNs transport information across a graph in a straightforward (non-loopy) way, and PGMs can propagate information in crazy (neverending loops) ways when doing belief propagation...