That is simply untrue. Yes it most certainly does happen. Obviously not to you, but that doesn’t mean “women don’t do this”.
Ultimately this isn’t about men or women but basic non-personal behavior. Being behind a screen provides a level of disconnect which enables people of all biological categories to say or do things they wouldn’t do in person. While seemingly more common among anonymous systems, it is also quite prevalent in non-anonymous electric systems. You just don’t see or often recognize it as such. It is also a function of effort.
For all but the last decade mankind’s primary interaction with her fellow human has been direct and personal. This rich communication method not only provided many observable feedback mechanisms but also a proximity filter. It is commonly brought in the context of the “keyboard cowboy” or “keyboard commando” as well as variations thereof.
This aspect goes to people online saying they would “punch you in the face” if only you were in front of them. In reality this is vanishingly rare and is nothing more than false bravado and posturing. But the underlying mechanisms are the same for sexual aspects.
Flashers and streakers have been around for generations. Yet they are a tiny minority of the population. The internet hasn’t changed this, it has simply made it more accessible. Just like any other form of stupidity.
Treating this as a “man thing to do” is not constructive, nor accurate. This is an underlying communication form that mankind is having to learn how to handle. The ease with which we can send bits around the net, and the speed of it, lowers the barrier of effort. I’d bet if that guy had to make an oil painting of his parts, shlep down to a post office, spend a chunk of money for postage, and then wait a week for the response he wouldn’t have done it.
The difference is the low cost in terms of money and effort, and the non-personal nature of remote electronics — not anatomy.