Feminine in the sense that the hair piece gives us no practical or functional advantage in our primary, biological, masculine roles of protector, hunter and warrior. You can argue that when you have hair and look better you'll close more deals, sell more, get more promotions, etc. and therefore be a better provider for your family and that is, of course, true but my argument doesn't pertain to modern civilization and acquisition of fiat currency but raw, atavistic urges and purposes.
You can also argue that a hair piece will help us "lure" and procreate with many more women. If Ted Bundy had been bald, he would never have lured and raped so many attractive young women. And that's probably true. But the act of "luring" itself is strictly feminine. Traditionally, for thousands of years, men didn't "lure" or have to "lure". They conquered and took things (and women) by violence or concord between clans/families.
Hair pieces are strictly for looking "pretty" and women are meant to look pretty. Men are supposed to be strong, brave and know how to fight.
Men who participate in the most aggressive, full-contact sports (rugby, hockey, mma, BJJ, boxing) don't wear pieces because they'd be nothing but a hindrance. Meanwhile soccer players are justly called "prima donnas" and Andre Agassi was so obsessed with his "pretty boy" image at the top of his career that he almost lost a grand slam because his hair piece was falling off (you can read about that in his autobiography). Image is very important for landing good sponsorship deals in feminine sports where the skillset isn't transferable to the real world. But in violent, masculine sports your image is created by the fact that your skillset (often combined with a big, powerful physique) makes you one of the baddest and most feared men on the planet. Being good-looking is just an additional bonus in that case.
I take my piece off when I spar at the gym (a few times a week). Every time I do it I say "Here comes Gargamel!" or "Gargamel mode activated" (my temple hair is long and I have the typical "pedophile look" at this point without the piece). I tried sparring with it but I couldn't focus at all as I was constantly worried about the piece getting damaged and/or falling off. I could actually imagine many men in pieces avoiding conflict/altercations/confrontations in the real world or avoiding participation in combat sports in general just because of their piece. Again, a feminine mindset. "I'm not going to fight/stand up for myself because I don't want to break a nail."
That's just how I see it. I definitely feel that my hair system makes me more feminine than masculine (in the eyes of those who know about it -- and many know both men and women). By comparison, I also take steroids, but in addition to the cosmetic/aesthetic benefits, steroids also increase my strength, performance, vitality and libido. Furthermore even the cosmetic benefits are masculine as I'm bigger and more intimidating and therefore garner more primal respect from those around me.