It's normal that Hara-sensei included Seth, since he drew him about a year ago, and there was only the initial event with the two of them. If it were now, it's obvious he'd include the Proxy instead of Seth, since Jane does seem to have a certain attraction to the Proxy. They've had several interactions at events, and they even went to the movies. I'm not saying it confirms she likes him, but it's obvious the developers are giving them more interactions like that. So you can already guess where the ship is headed.
I think it's because of Maho and Erika's speech bubbles 19 seconds in. Maho's could be explained as just her loving her sister (though the fandom often portrays her as really loving her sister), but Erika has the same speech bubble with Maho.
I'm pretty sure they they haven't gotten that far in the story, but even then I'd understand them leaving it out. I remember when talks started up about this potentially being adapted roughly a few years ago, a friend of mine mentioned how some people would likely fetishize it rather than have their takeaway be that it's a traumatic experience for Mark.
Though seeing as it is Amazon, I wouldn't be surprised if they cut it for being too uncomfortable, but they have had a lot similar or worse scenarios both in this and their The Boys series, so I could see it going either way
That's the (possible) cowardice I was talking about.
I SPOT A WAVY WACKY INFLATABLE TUBE MAN! I saw one of these the other day and I stayed mesmerized for almost ten minutes. Then I realized I was as easily amused as a dog and I skeedaddled away.