They were accepting bitcoin using coinbase plugin and i think this decision is due to some regulatory complexity between those two platform. There may be also not many advertisers who have ordered from them in this three years, so they may have thought of removing it rather than getting into any legal issue. But they may soon realize the potential of bitcoin and will open up their doors again for bitcoin.
I'm thinking that this is the most likely reason for them stopping their Bitcoin accepting platform(s), since the US government is going around and getting a bit tighter on companies like Coinbase it would make sense for them to have to back out due to mounting pressure on their company via the IRS.
Sad to see it go, but it'll probably be back one day.