Yea, no.
This is only true if you pretend the kink is exclusively limited to seeing the MC get blown the fuck out (ie. the Western Cuckold fetish). But it isn't.
The Japanese 'Netorare' genre is filled with stories that either imply or flat out tell you that the guy the FMC has fallen in love with is just using her for sex and that he will dump her as soon as he gets bored with her. In those stories, the FMC's degraded, fallen state is just as much a part of the kink as the process of her getting stolen from the MC.
Of course, it's not always the case, but it's so normal that you really shouldn't be surprised if the FMC ends up alone and miserable at the end of everything. After all, it's a normal part of the kink.
So, if you can say that wanting to see Sophie get used up and thrown away in this kink is a 'self-own' and makes someone 'similar to an incel', then I could say that wanting to see her get a happy ending in this kink is a 'self-own' and makes you 'similar to simp.'
Then again, maybe we could all be adults and recognize that people come to netorare for different reasons without resorting to name calling?
...No?
Fine, whatever.
And you should have chosen not to. Learn to recognize bait, friend. Hopefully what I typed above makes things clearer for you.