Hate, I'm not so sure; "root against," definitely. Some good villains you despise; some good villains are fun to watch; the common factor is that you cheer when they finally get their just deserts. Either way, Bob seeing Gunn displaying simmering hatred for Luthor is a bad sign, and a symptom of what makes Bob such a terrible writer (and in this case I don't mean his syntax or grammar).
A writer who hates any of his characters is not going to portray that character fairly. From Luthor's perspective, he's not a bad guy at all: he's trying to keep reins on a dangerous, near omnipotent space alien while making a few bucks in the process. If envy of Supes' powers should play a role in that, well, that's just human nature. A writer worth the name will at least understand his villains' motivations, and if all the cylinders are firing might even have a great time writing them. It's similar to actors' love of playing villains: they get to break the rules and spend much of the story winning, and therefore have all the fun.
A writer who turns a villain into a hate object, either one taken from his personal life or from politics, pop culture, or what have you, is being foolishly self indulgent. If it's someone from the writer's life, it's petty, pointless, impotent revenge. If it's a Trump ... well, it's also those things, but it's also liable to be a piece of crude propaganda.
It's entirely possible, of course, that Bob is projecting and that Gunn has done something more interesting than what Bob sees (which is absolutely what Bob wants to see, so he's going to whether it's there or not). Whatever you think of Gunn, Bob is a dreadful critic and what passes in his mind for analysis can't be trusted. As usual.
I was skimming the DC thread and one of the posts had an alleged plot synopsis, which seems to line up with what I've read in some of the early reviews. The synopsis mentioned that at one point, Luthor
kicks Krypto. That's right, the big bad of the movie literally kicks the cute puppy (allegedly).
Now, is that a simple way to make a character look evil? Sure, nobody likes people who hurt animals. But is it an
effective way? I'd argue that it isn't. You'll get that kneejerk "omg how awful" reaction, but when paired up with the other allegations of Gunn using Luthor as his stand-in for everything he hates, it screams to me as though it's a cynical ploy to get the audience to agree with Gunn. "ElonDrumpf is so horrible that he kicks dogs! Surely you wouldn't be on the side of a puppykicker, would you?"
You can certainly use such a device in an appropriate manner, but a truly compelling villain wouldn't need such a cheap shot to get the audience to cheer the hero on. Maybe Bob's reading too much into this, but it wouldn't surprise me if Gunn is using this tentpole movie as expensive therapy like so many other directors seem to be these days, instead of reflecting that maybe, just maybe, making a bunch of posts about pedophilia wasn't the smartest idea in the world.
This is a slight tangent, but I'm reminded of a post from someone that Bob retweeted (I think it was that Cargill guy?) who echoed his insistence that directors shouldn't give fans what they want, but what they didn't know they wanted. This is a nice sentiment, but it is frequently (hell, almost always nowadays) used as an excuse for Hollywood's godawful adaptations of other media.
Fans are usually pretty easy to please. As long as you don't egregiously fuck things up, they'll generally go along with what you're doing as a creator. This means that you get some leeway with regards to the story, and a good writer will use that to their advantage to add twists and turns that the audience isn't expecting. Long before Roundhead Johnson made it into a meme, "subverted expectations" was generally a positive thing, helping to keep a work fresh and engaging.
But when you push too far, that's when you get the backlash. Making an established hero into a dopey wimp, elevating an obvious author's pet in their place, throwing in hamfisted political references that date the work before it even hits stores, shitting all over established conventions for no reason other than you can, and all of this
especially when taking on the task of adapting another author's work...yeah, no wonder fans aren't too happy with you. To dress this up as "giving them what they didn't know they wanted" is just retardation of the highest order.
There is at least a kernel of truth to Bob's "never listen to fans" platitude, and that is that they are sometimes too close to the work to be able to discuss it objectively, and their ideas can often veer into bad fanfiction territory. That said, I would
always choose to listen to even the dumbest fan idea over some dorky leftist know-it-all who just wants to use the husk of an established work to push their retarded message.