What would happen if M&S just put these knickers in the menswear section and called them men's pants or whatever? I wonder if they'd continue to get all the 'sexy panties' comments and eagerness to try them on in the (men's) changing room, or if that's only naughty and fun when actual women and girls are involved.
Idgaf if you want to wear knickers mate, fill yer boots. If you want to make nonconsenting women uncomfortable by performing a fetish around them that's a separate matter.