Then they would have to explain why.
I don’t think they need to explain every decision they make.
btw, being dan l’kaf zchus doesn’t mean being stupid and thinking that an aveira is not an aveira. This is clearly assur according to Hilchos Loshon Hora.
You are entitled to your opinion that it’s assur. I happen to think you’re probably right. You’re not entitled to say motzi shem ra on an organization by saying they don’t care about lashon hora, when you know quite well that in the past, they have deleted (when pointed out) lashon hora and probably delete a whole lot more which never got approved to begin with.
Again, I’m not telling you to change your opinion about whether this particular case was (is) assur, rather to not accuse YWN of deliberately violating hilchos lashon hora.