the hate is wild to me, I've literally never seen this reaction and have played plenty of vns with intra harem sharing the NTR lovers really latched on
and sharing isn't NTR, atleast to english speakers since we use the word sharing, NTR is exclusively used to refer to cheating or stealing girls and almost always cringy fukbois stealing girls. yes I know netorase exists but the only time I see people use it is to say "well akshually sharing is NTR because of this other japanese word that people don't commonly use" to which the answer is when people use that and aren't trying to hate or push for the inclusion of full blown NTR they use NTS to differentiate them
lastly not liking sharing with other males is a breeding instinct (females can't impregnate your girl) and so long as they stay with you it's all just fun