This game works with the harem, even if solely for the fact that MC can literally be the pack leader and whomever watched even a tiny bit of wolf lore - the pack leader has absolute control over his pack and all his betas will never challenge him.
Remember that MC starts this game with a GF and they go into the biggest step of their relationship - moving in together. MC in this game has a GF, is not run of the mill, not a geek, not a beef cake - MC is a guy who got a girl head over heels for him - this is the kind of fun every and all human beings crave for as a wonderland story where the girl chooses them - MC has already been chosen.
Now, MC is in a competitive environment and sex is not presented as a tool to get girls, but as a tool to appease their idea of friendship.
In any environment with many colegues who feel a duty to engage with MC, his ability to come out on top from confrontations will make him desireble.
According to many hook up artists - girls who see other girls fawn over a guy will desire that guy like a commodity and girls will always enjoy the courtship of womanisers for the thrill of making fun of him is nothing else - MC is written as a commodity and everyone wants a piece of him - to beat up - his fellow wolves, to romance - his fellow ladies , to enthrall in their activities - the fight club leader, the wolves leader, the witch, the medusa, the vampire.
MC has experienced the peak of his relationship bangign his long time GF and being goaded into moving in with her. MC has it in his mind that girls want exclusivity and MC also has a very good idea where this is ehaded - his long time GF showed him where exclusive relationship could end up in the best scenario he already lived briefly - mindblowing sex and moving in with your bethrothed.
On the other hand, this game proposes the harem path like just another path, so to this point, the greatest rewards for even the girls who might fancy a harem out of curiosity if nothing else, their scenes will be lacking if MC is fooling aroudn with too many others.
These branching path LIs games never really work
I suspect the Dev simply realized at some point that he could get more money AND suffer less stress trying to write and render a million branching paths for all the LIs if he just gave the people what they want.
I say appeared to be because now I'm not so sure that wouldn't of been preferable.
Instead we have a supossedly mature, intelligent student studying psychology.
That in his internal monologues atleast comes across more like a creepy aspiring serial rapist.
As it stands right now, MC is better off with a singular relationship with his wolf babe .. .or his medusa ... or his vampire - these three give MC the most satisfyingly mindblowing satisfaction ...
Going for contending girls could work going into the harem roadblock, where MC hits the roadblock of being streassed too thin to make any of his relationships work.
MC is clueless .. which is not to say the girls are any better, as the wolf girl chooses MC after her former BF literally leaves her for dead in the trials- the dickest of moves for any alfa if I ever saw one. The Witch speaks of exclusivity - dissing the medusa, but at the harem talks, she just says she is not more than a hook up and she likes it like that.
The vampire is turning her whole persona and clothes on a dime, MC cannot get a lock on her actual feelings for too long.
So long, this has been the experimentation phase .. MC can now see and make the player have a somewhat informed decision about what he wants to do going forward in this game.
I mean She has a beautiful Big Pointy Tail She can Use, right? 
