Your points are somewhat well taken, but you have to be able to support them with some fundamental or technical analysis. Just saying that the stock price is high or that they are growing too fast is just an opinion. Yes, the stock price has been on a tear since last March, but it hasn't gone parabolic and instead appears to be going along a 45 degree angle (about the fourth time I mentioned that term today). Check the RSI to see if it is getting overbought. As for growth, that is the model for how these MLPs work. They grow by buying smaller outfits or building more capacity. They have metrics to achieve before they buy which helps avoid overpaying. I think they said that the latest propane acquisition is accretive.
I have read several posts on this stock and many other MLPs. Many posters are concerned about overvaluation in this sector as the MLPs have all gone up. Many are comparing the yields and digging out the old metrics for how MLPs were valued. Many of these MLPs have used the decline in interest rates to refinance their debt at low rates. Others have used the rally in their stock price to issue more equity to pay for acquisitions. On a whole, the MLPs are in much better shape than when the hedge funds were liquidating them en masse back in the Fall of 2008. Many are poised to resume distribution increases. And investors are getting more comfortable with the underlying businesses and their finances and are no longer afraid of the tax reporting as they look for relatively safe and growing yield.
A few final points. P/E ratios mean nothing for MLP's as the standard metric is to use the DCF coverage and growth. The GP may have greater distribution growth than the MLP.
It's good to be cautious, especially when the economy is still in the tank and the system is teetering, but notwithstanding a financial meltdown (the chances of which are admittingly higher than what we ever thought), companies that can grow will still attract investment dollars.
Heating needs across their service area for the next few weeks should support their bottom line for propane distribution. The grain drying season isn't quite over yet either, and should account for a LOT of product.