You're not "forced" to do anything. If you don't want to see those scenes, don't watch them. Simple as that.
Also, Eric is needed for the story. As bad a writer DS is, he did get that part right (and no, I'm not talking about the NTR). All Max does is peep on his sisters and mother. That's it. Nothing more, nothing less. It isn't until Eric shows up and the rest of the family falls in love with him that Max realises he has to step up his game. Eric pulls Max out of his comfort zone and motivates him to do more and be more agressive.
Uh, no, those guys are like the macho guys who are so "secure" in the masculinity they think guys who dress up as women are queer, while real men have no problem dressing up as a woman because they know it doesn't change their sexuality (see Tom Holland in his Lip Sync Battle). Players that hate NTR are the ones who are afraid they could lose their women to someone else. Real men capable of taking care of their lady's needs don't care about it, because they know it'll never happen to them (or will be the ones doing the NTR).
I said "forced" with " because if you want to see a sex scene in the game that's the only way right now, for the MC to start having some kind of sex it's still a long way from now, so if you want to fap with this game, right now you are "forced" to see a NTR scene.
What Max needed was a way to make him wake up, to make him realice that he could lose the girls, his family, if he does nothing. Was then needed to bring Eric to make that happen? Not really, there could have been another ways, maybe even subtle things like they are thinking of starting to date, or are already planning a date with someone. Was it needed to bring Eric home and start fucking Ann and trying to fuck them all to wake up Max?? Again, no, it was the easier way. Like in those stories were the mc is really in love with her childhood friend but he didn't realise it until she stars dating someone else. That's the easy way.
Would cause the same wake up call in Max if Ann started dating Eric, brought him home once so we know him, but she decides to go slow with him, instead of almost living together since they start dating? Yes it will. I'm not a writer but all Max needed was a wake up call, it could have been done way better than having Eric trying to steal all the LI of the MC and succeding almost instantly with the mother. Let's not forget that this is suposed to be an incest game, but since Eric is the focus it really isn't one. It was a mistake in the original, introducing him without a way to stop him before he starts getting serious with anyone, including the mom, and it's a mistake again here. He is one of the most hated characters for a reason.
Players that hate NTR aren't afraid they would lose their women, well at least I'm not, I just don't like to see NTR in games, I tend to SI in the MC so I could enjoy a game more and I don't want to see the LI of the game being with others, that isn't a fetish I like, I don't like NTR or sharing of any kind, hell I don't even like when some girl members of the harem of the MC in an harem game go and have sex between each others if I don't have a say in it. So why would I want to see in an "incest" game some kind of NTR? I don't play to see things I don't like, it has nothing to do with real life, I play games to have a good time, having NTR in an incest game withot having a way to prevent it, it's not fun. More when the dev even said he doesn't like Eric at all, but still goes and do lots of content with him.
He could have looked for a better way, another way to make the wake up call on Max, just with an option to stop Ann from having a relationship with Eric if you didn't want to see him, or let it happen if you want to see NTR, there wouldn't be a problem. Max would get his wake up call, in a sense that they won't stop looking for someone outside the home to date if he doesn't step up his game, adn all the NTR lovers will get his loved Eric. There all people happy. But I guess that calling this "another story" was just a name, it's easier to follow a bad developed plot and game and only change a few things, than actually do "another story".