I was going to drop in here and say, "Bob, you missed the point.", but it looks like other people already called him out on it.
I'll just add this: I am a writer, and I appreciate a wide variety of media and genres. There is a difference between a bad ending and a broken ending. ME3 was a BROKEN ending. It did not fit, it did not function.
To compare it to Cabin, which had a brilliant, meta ending, is insulting to the move, the filmakers, and both audiences.
I'm not going to be pedantic and spell out why Cabin's ending worked. You're a smart guy, this is what you do for a living, there's no need. Nor will I rehash the (very tired) debates on ME3's ending. There are entire articles and videos done by people far more invested than I ever was into "why this fails at a basic level".
Yes, there are people who miss the ending of why Cabin existed, and who, in raging at the ticket counter (I saw this, it was hilarious) manage to BECOME the elder god's rising for blood.
Yes, there are people who were pissed at the end of ME3 because they didn't get formula happy-rainbows.
But the bulk of the objection to ME3's ending wasn't "this was bad", it was "this was broken", and there is a difference. One you don't like subjectively. One does not function on a basic level. The fact that the creators never offered up any cohesive defense of their ending, but only hid behind the blanket statement of "it is art" to ward criticism, should clearly show that many of the writers realize that it is not functioning at the level they'd wanted.
They're doing an Extended Cut. This may still leave the ending as a "bad" ending, which will piss a lot of people off, but it should HOPEFULLY resolve the problems of a "broken" ending, which created the Re-Take backlash.
EDIT: EXAMPLE INCOMING... There is a definite difference between, "I didn't like that ending", and "Jesus Christ, that ending just took a poop on every scene before it, and I feel guilty by proxy for witnessing it." I hated the ending of No Country for Old Men. It was grim, it was pointless, it was depressing... and that was the point of it, so I respected it immensely, even as I thought to myself, "that really sucks, I was hoping he'd make it out". I never had the urge to go online and complain about it, because it WORKED. Hell, I chuckle about how deep it cut me, because I was that invested. It made a point, it made a statement.
The best statement that ME3's ending managed to make was "herr derr" as it bungled its own continuity, its own themes, its own characters, its own... well, just about everything. Seriously, go watch the videos with an open mind. Better yet, Bob, go play the damn games, then comment on it, since you seem to lack the ability to change perspective on this type of issue without personally investing.