CoinTelegraph published an article about this on their site. It's likely that CoinDesk underestimated the community's reaction towards the irony of a BTC news site not accepting BTC (technically this isn't correct - see below) on their deals page:
http://cointelegraph.com/news/113674/coindesk-launches-deal-site-without-bitcoin-supportprobably has to do with the fact their deals are not CoinDesk-owned products. They use a third party site which is not accepting BTC at all.
This is just a referral system, nothing more, nothing less.
This is true. In fact, the company they are using seems to be
StackSocial. Thus, CoinDesk isn't actually selling anything. They are simply referring users to buy products from StackSocial and they get a small percentage of the profits of each sale. Technically since StackSocial is a Groupon-esque site, you could say that even they aren't really selling anything directly themselves either.
The use of StackCommerce also explains why CoinDesk Deals doesn't currently accept bitcoin. Since it is actually StackSocial that is selling the deals and not CoinDesk, it isn't up to CoinDesk. Until StackSocial accepts bitcoin in some fashion, neither can CoinDesk Deals.
A lot of people have already suggested using a solution like BitPay to protect against BTC volatility but the reality is that it's a bit more complicated than that. Some sort of agreement will probably need to happen between BitPay or Coinbase and StackSocial.