Never seen the movie, never want to see the movie ...

Yeah. Movies where European stars wallow in senseless nihilism are far better.

I remember it to be a film about revenge and survival. If Ebert thinks it should have some great societal message for us that it didn’t, that’s his view. I was happy to see Burt Reynolds taking out the trash.

Ebert was wrong in his evaluation in that the movie does make a significant statement involving the events thereof (no spoilers):

After the thoroughly disturbing scene the movie's infamous for, a moral crisis takes place in the remote forest where the four members of the party must vote on a decision. Lewis (Reynolds) and Drew (Ronny Cox) make their cases and the other two must choose. Count me with Lewis. At first glance it would seem that Drew is arguing the side of the wimpy moralist, i.e. contact local law enforcement and allow the courts to settle the matter. Is this the real reason he takes this position or is it simply because he doesn't want to risk becoming an "accessory to a crime"? Actually, Lewis is no less the moralist -- after all, he makes a moral judgment and unhesitatingly acts -- it's just that he refuses to risk allowing the local authorities and a potential inbred jury (likely related somehow to the hillbillies) twist his just and necessary actions into a crime.

As to Ebert's criticism that what happens is "fantasy" and unrealistic, it isn't. "Wrong Turn" (2003) is a more modern horror film that, generally speaking, tackles the same subject as "Deliverance." The problem with "Wrong Turn" is that it's full of horror clichés and cops an unrealistic vibe. Don't get me wrong, it's an entertaining flick for what it is but I was never able to buy into the story as a potential reality; hence, I didn't find it horrifying at all. "Deliverance," on the other hand, is totally realistic from beginning to end and is successfully horrifying precisely because it COULD happen.

And anyone who doesn't think that perverted yokels exist in the secluded backcountry hasn't been around much.

I’ve often found that Ebert had trouble understanding the ideas and themes in the movies he watched. I never got his popularity and fame. That said, this movie had pretty mild violence even for its time.

I just want to pop in here and mention that it's not like they track down the rapist and tie him up and rip out his fingernails or something like that. That would be more gratuitous violence like you're talking about. (Think super rape-y revenge flicks like I Spit on Your Grave.)
In the movie, Lewis and Drew bank the canoe by the other one and then see Ed(?) on his knees with a gun to his head and two strangers talking about raping him. Lewis then shoots one of the bad guys (happens to be the one who raped Bobby) in the back with an arrow, and the other bad guy takes off running.
They don't just leave the guy's body there and hop back in their canoes (as I figured they'd do), but instead they have a huge thing about justifiable homicide, "jury of inbreds", etc., trying to decide what they should do with/about the body/homicide.

To me, that in itself made it more realistic than I was anticipating.
I mean, yes, assuming you never get raped in the woods by some strangers, and assuming you never have to kill someone who's raping someone in the woods, I guess you could claim it's unrealistic in that sense. But it was a hell of a lot more real than most of the garbage out there to which you're referring.

And you're right, a ton of movies got really bad with glorifying violence for violence's sake, but if they did that after this movie (because of it or not), then I wouldn't say that this movie is the problem or cause; it doesn't change that this movie is great for what it is.
If other people made shitty movies because of this one, that sucks. But this is still a great movie.

Hell, there were more white-water rapid scenes in this movie than violence, and those scenes were the movie's biggest standouts to me while watching it. That was some realistic shit there, not all CGId like these days.

Anyway, I hope you change your mind and consider watching it someday. It's so much more than a rape scene in the woods.