Indeed. Mass Effect fans weren't pissed off because they felt entitled to having their every whim catered to, or demanding to have some impossible to achieve work of super fiction, they were pissed off because the ending of Mass Effect 3 is shit.
It's an unsatisfying incorreherent torrent of garbage for the last hour+ of the game, with the final 15 minutes just a festering pile of unsatisfying bollocks. And that's even after the extended cut.
All the anti consumerist arseholes yelling about 'entitled gamers' never seem to take this fact into account. As a product, Mass Effect 3 was fundamentally broken and substandard because of that ending, which is particularly irksome given it's importance to the overarching narrative, and given the fact that the prior games endings are fucking amazing.
People go on about the fans hating 3 because it didn't end in sunshine and rainbows, but ME2's ending is almost universally adored by the fans, and in it the entire cast can fucking die, including Shepard. It can be as miserable as fuck, and it's applauded for it, because it's bloody brilliant.
So yeah, if Valve are seriously pointing to the fan reaction to the ending of ME3 being utter shite, as a reason they don't want to make HL3, then they're being anti consumerist pricks.
As is anyone who calls angry customers, demanding for a broken product they paid money for to be fixed, 'entitled'.