Of course. Everything we know know is that EA said plenty of times "we wanted to sell our games with expanions from the beginning" and "our lawyers give our green light to include expanions" and GOG says something like "our office never heard anything about that" (office, not lawyers...) , I really can assume that GOG did a mistake, not EA.
But those were from people who, IIRC, had little directly to do with GOG's dealings with EA, and if they were, would they start making public statements about a private business contract between their employer and a business partner?
Look, I think this isn't a good situation either, and GOG is suffering from a lack of transparency about this, and I hate it as much as you do - I just don't think it's a good idea to start pointing fingers until we have more to go on than just circumstantial evidence.
Everything you do in business is a risk. EA expansions are less risky than indie games on GOG, i think.
I meant risk in terms of "Oh, Rights Holder XYZ that we didn't properly account for is now suing us for X-percentage of the profits we're getting from this IP...", or "Oh, oh, we really should have tested the game with the expansions more because Expansion X breaks game Y or on x86-64 bit Vista/Seven." Granted, I think the former would be more likely than the latter.