It is not the pink. Pens that were simply pink and purple with normal packaging would not get a negative reaction, except from people disappointed that the ink wasn't pink and purple. It is that they are marketed as "for her", as if only women can use pink pens, as if men cannot use pink pens, and as if women can only use things that are pink and purple. It is hardly the only thing marketed this way, either.

This is why many women go through a HATE PINK stage, and it's legitimate. When you're treated as if you're expected to loooove this color, and this color is considered by the broader culture to be girly and therefore weak, but you are a girl and therefore you must be girly and therefore weak and therefore love pink, hating pink is one way of rebelling. I'm over that now, but that doesn't make these pens any less ridiculous.