Yep, it's inane. It doesn't mean anything in the real world. Of course being kind generally is right but life is full of complicated situations in which we might need to be firm, or critical of others. We're allowed to have boundaries. We're bloody adults ffs, we don't have to include everyone. It's another stick to beat women with, just a continuation of the age old insistence that women must be caring and accommodating, no matter what.
I also know some truly bloody awful people who are all over the #be kind narrative. Of course, if they say it on social media it must be true!