Of the authors 3 reasons, I would agree with 1 and 2 however not with 3 as he is applying wrong valuation metrics to MLPs. I would say that his first reason is perhaps the most likely reason for recent poor performance by MLPs, like on Friday and Monday when they underperformed the overall market.
sometimes I feel like no one follows the economy or the market as a whole and just checks on the price of this and wonders "what's going on". Have the MLP's been down more than the S&P over the last 6 weeks???? Come on.