There is nothing sexist about Cam's comment. He's also not laughing directly at the reporter in her face, he's clearly just tickled in his own thoughts. He's reflecting on how unique and neat it is for a woman to ask a question about route running and being physical against NFL defenders. It's no different than a fashion model laughing to herself about a male fashion reporter asking a question on how models make a cat-walk look so easy in high heels. It's funny because you're literally asking about something you will never experience even though you've seen film of it happening.
I'm not saying it's unusual for women to cover professional sports, just as it's not unusual for men to cover fashion. But no woman has ever played WR in the NFL and I think he's just being playful with that. There was no intent on Cam's part to act like she didn't have the right to ask that question or that he didn't take her question seriously. He did. He answered it. And I'm sure he's sorry she took offense to it. That clearly wasn't the intent. He's not making fun of her, in fact, it's quite the opposite. He's identifying how much the comment stands out to him. He went on to answer her question and look her in the eye and be very serious about it. I'm sorry that Cam happens to be a human being. He's an easy going guy and laughs about a lot of things.
Cam wants people to be individual and be themselves. He breaks the mold and promotes that of other people. I'm sure he'll encourage his daughter to strive to the the best at whatever she wants to be in life. Cam was simply making light of the comment like he does in every single press conference he's ever had. Cam is always joking around and ribbing reporters. It creates a fun and relaxed atmosphere. No different than how family and friends rib one another at the dinner table. That's part of the whole human experience. Being able to not take yourself too seriously all the time.
There is no reason to be up in arms and defensive about this. He was not disrespecting her. He likes to have fun with reporters all the time. Remember when he made fun of David Newton for being old and out of shape for the Play 60 event? Why weren't you outraged about ageism then? Because it was all in good fun, just like his comment here. This is 2017. With shows like South Park having been around since 1997 we should have come far enough as a society to not be so sensitive about such things. Work place harassment and discrimination is a very serious thing, but Cam did not mean harm and is certainly not sexist.
I guess now Cam just needs to act like a robot each press conference and not be personable at all. Or he needs to walk out whenever he is asked a question he's not comfortable with. And he should never be criticized for it.