It's "badly written" because if the lawsuit is frivilous then it might still cost a defendant a ton in legal fees they can never recover. I assume the logic is "if they could counter-sue for legal fees (which no person could feasibly cover out of pocket, especially if they're being discriminated against) then they might be dissuaded from suing in the first place". The idea is to prevent fear tactics scaring off legitimate complaints. "If you lose, you're financially ruined".

So then the only defense is for the court system to consistently throw out frivolous lawsuits. But it can't get all of them.

How can the law be written better without falling afoul of the 14th Amendment? Surely it's not acceptable to write laws that say that "Women" only may benefit from it.

In terms of audience, it can't be better written. It can't realistically favor any particular group without being used as a tool for one group against another. Doesn't mean it will result in fewer frivilous lawsuits, just that one group might have a harder time filing said lawsuits. You could make laws that target specific issues, for example, denial of leave for medical issues specifically related to pregnancy. Men aren't going to be taking advantage of that any time soon, but one could complain it's unfair that there isn't a similar leave for men having children or who wish to attend to their wife when she's in the hospital. Ironically, many "progressive" nations, especially in Scandinavia, offer paternity leave for this reason.

In other words, it's not poorly written because men being discriminated against can use it. It's poorly written because it gives too much power to plaintiffs with no counter-balance or consequence for stupid lawsuits. Lawyers have a lot to gain from them and nothing to lose, because someone is paying their court fees regardless.

If he really wants to imply it's badly written because exclusive events are okay for one group and not another, then I simply disagree. Either you can have events that discriminate on who is invited or everyone must sell tickets to all sorts of people. And like the article says, if you're worried about one group you dislike "misusing" something that is a blanket policy, then maybe the problem isn't the policy but your idea of who should be allowed to do what.