I think harsh speech is simply unkind speech. I run a small local non profit entirely with volunteers and one of the first rules I learned is that how we speak to one another, whether in person, in writing, or over the internet, matters. I think speaking kindly and with respect to others allows them to be open to hearing what you are saying. Who among us ever responds to unkind speech in a positive fashion? Human nature is such that when spoken to harshly, we close up and stop listening, so speaking in an unkind manner is simply self defeating. It took me a long while to realize that if I wish to get my point across I need to find a way to do so kindly and with compassion, regardless of the information that I need to impart and regardless of the issue involved.
Yes, this is the internet and for some reason, perhaps because we are anonymous here and therefor not held accountable, we tend to be our rudest, unkindest selves. However, that is unproductive. I think that most of us simply tune out when spoken to that way, even on the internet. Just because people behave badly on a regular basis, is not a reason to say that because this is what happens, that it is okay. Right out of the gate, the original poster on this issue was criticized for his/her observation.
I know that kindly speech on the internet is possible. On one site (and one site only) that I belong to, one virtually never hears mean speech. Posters seem willing to follow that old adage "If you cannot say something nice, do not say anything at all". As a result, I am still visiting on a regular basis and learning. It is a safe site. Should not a Buddhist site adhere to basic rules of kindly speech?
I was discussing this problem with a friend because I had felt compelled to leave a site I loved because of the cruel speech and she noted that perhaps good manners are simply disappearing because we are losing the ability to respect one another. Is that true? Are people today just ruder and meaner and more selfish, unwilling to allow others their opinions without pounding on them? Is that what humankind has devolved into? I hope that is not the case. I hope it is just that the internet encourages petty behavior. I hope that this is not the future.