He quotes Nietsche, in particular interpreting the ubermensch or child as "master" so that it describes it himself, his gloating animation is labeled "evil" in code and that label fits, he blackmails Lena into a fancyier form of prostitution, ordering her to insert sextoys into her, all under the label of artistic expression. Utter disregard to the common folk, classist and elitist. He is too educated to argue with ignorance, he knows what he does makes the mayority suffer and very few benefit. Compare him, Agnes, the mayor candidate and Arthur VS Perrys dad, homeless guy, Emma, Ed and Molly. Hmm, I wonder who the wholesome, friendly, morally upstanding people with integrity are in these two groups.
He is morally bad, the current portrayal of a misunderstood well meaning extremist isn't consistent with his previous introduction and buildup.
While ORS very likely won't lead to rape and murder as GGGB could, Seymour and Axel were the closest you have to engaging with vile, corrupt scum, without them directly being rapists (Axels scenes are forceful and dominant, but sort of consential in porn logic as in Lena could back out and just decides not to).
Being able to quote Nietzsche makes you evil? Oh my God, now I know I am evil!
Joking aside, while Nitzsche has some big blunders in his philosophy, there are parts where he nailed it, no matter what the Naysayers (many who never read anything written by him) blabb.
But philosophy aside, most of what you describe here happens if you antagonise Seymour from the get go, it simply does not happen if Lena and Seymour have a good relationship. In addition, if Lena is close with Seymour and Emma, Lena can sponsor a talk between Seymour and Emma (in some future update).
As for the morally upstanding people comparison, it might be cynical, but I would take a competent as... mayor, who get´s at least some things done over the morally upstanding, but incompetent mayor Perry´s Dad is, whose failure hurts the whole city, any day.
Seymour is morally really bad only on the antagonise him from the start paths. His current portrayal is consistent with the Seymour on the Lena and Seymour have a good relationship paths.
It's very easy being nice to the people who are nice to you. The marker for goodness isn't in how you treat those close to you, but how you treat people who you don't directly stand to gain from treating them nicely. As an example holding doors open for a date is nice gesture, but doesn't actually reveal your character because you could be doing so as a way to get in good standing. On the other hand holding the door open for strangers who you have nothing to gain from probably reveals more about your character.
All that to say that of course Seymour is nice to Lena if she is nice to him. That doesn't change that he is a blackmailer. He directly blacklists Lena from her main source of income in order to get her to work for him and satisfy his fetishes. On the paths where Lena is into him he still blacklists her before proposing his contract to her. If Lena tries to refuse the blackmail is brought up. Also, saying that these practices are industry standard is not actually a refutation of the claim that he is immoral. It just means that the industry standard is to be immoral.
Nothing from this Seymour update has changed any of the facts or contradicted this understanding of Seymour. The only thing we learned that besides being a horrible person, he also is inept.
You are argueing with meta knowledge here, since we can see Seymour (or other characters) at their worst if we play enough paths. But that is futile here since the various paths represent different universes. On the paths were Lena and Seymour have a good relationship, Seymour is not a blackmailer. Unless it was reworked during an update, if Lena and Seymour are close, he proposes his exclusive contract before(!) doing any blacklisting.
Besides, I never said Seymour is fully good or so, as your argumentation assumes. I argue that the Seymour on the paths where Lena and him have a good relationship is not an evil bastard. He is still im- or amoral in his choices, but he has growth potential and is nicer than many think. As I said, play some path variants where you can learn more about him.
The idea that Seymour might be actually completely innocent and nice older guy kind of doesn't quite align with how Lena is on more than one occasion rewarded Smarts points if she opts to avoid getting closely involved with him. I mean, if Lena having a relationship with him is supposed to be perfectly normal romance route, why is it a smart thing for Lena to avoid it?
As I wrote above, I do not say Seymour is a pidgeon feeding do-gooder. He is a shrewd business man, who is also im- or amoral with many of his choices. He is not really good, he resides in a morally grey area. Seymour as depicted in the game and the new update in special has the potential to get "better" (e.g. Lena can sponsor talks between him and emma, he is a lot more inclined to do the right thing if Lena and he have a good relationship and Lena nudges him to) Unlike Artur, Seymour has not gone beyond the moral event horizon so far and still has potential to become a better person, esp. if people close to him give hints or initiate stuff.
Nevertheless Seymour is, as said, mostly im- or amoral in his choices. Going by his favourtie philosopher I would say amoral. and this is a part of him for good. Even if Lena and friends can nudge Seymour to become a better person, part of him will stay amoral. And a Lena in a close relationship with him will undoubtedly be influenced by this towards a morally more grey stance. The couple smart points Lena can get is for seeing this and if she wants to stay a "pure" do-gooder.