It's debatable whether yet another big outlay of investment dollars is a positive or negative. Who cares if it helps the stock 20 years from now, I would like to see them shore up finances now rather than continued investments.
It's also possible that they overpaid--who knows. The market sure didn't reward the stock price for the buy. I wouldn't be surprised to see a 52 week low tomorrow.
It's this kind of nonsense that is affecting the stock right now. Traders taking advantage of broad negative sentiment throughout the whole market and refining specifically. This thing is trading at a little over 6.5x earnings. Earnings could drop in half and it'd still be fair-priced.