1. The services were overpriced to begin with. Seriously, the price of a brand new AAA game gets you a few quick database changes. There's not much in the way of cost to Blizzard, the only reason these cost as much as they do is because Blizz says so. These services shouldn't be free, I agree on that much, but the prices were too far too high, and are only getting higher.
2. Don't give me the bullshit about it being because of the Pound dropping. If that were the case, Euro prices would stay the same. It's a flimsy justification, at best. And you can bet prices won't be going down if the Dollar drops or the Euro rises. So fuck that noise. Yes, they are a business. Yes, they can set their prices to whatever they damn well please. No, I don't have to cheerfully swallow every PR excuse they throw my way.
3. It's basically down to Blizzard raising prices on their stuff (Hearthstone packs went up as well recently if you recall) because they feel they can leverage their brand into squeezing more money out of their customer base. They feel that the amount of money they'll lose due to customers leaving is smaller than the amount they'll gain due to the increased prices. It's a business move, nothing more. I for one have no intention of purchasing any Blizzard products in the foreseeable future. Granted, that's mostly down to there not being much in the way of actual products to purchase, but that's a different argument...