No, most women wouldn't be getting moist upon receiving a proposition from a colleague over work e-mail....because it's ****ing creepy and inappropriate, and guys that are creepy and inappropriate aren't attractive, regardless of their looks.
Good grief, you make it sound like the guy walked past her in the office, saw her name badge around her neck and then went back to his desk and emailed her to ask her on a date. It sounds like they'd had some interaction before, and yes maybe he was a bit premature on asking her out, but to be treated like that?
Let me give you some real world examples of my own. One job, I worked there for eight years, in those eight years, I either dated or had brief flings with six women. Four of which I asked out over email. I didn't just email them out of the blue, I'd worked with them and we'd had a laugh and a joke over a period of time and we'd be emailing back and forth just getting to know each other better. Not once did I get called creepy or inappropriate, and I wasn't reported to HR/pasted on social media/had my house burnt down by attacking hordes. One of the girls said no by the way, it wasn't a 100% success rate, but she simply replied saying her ex was back on the scene and she was going to give it a go.
The job after that, I had a relationship with one girl there, and I had flings with two others. Two of which I got together with via email (one of which asked me if I wanted to meet up via email). I was getting more into online dating at this point, so I was doing less of it at work, as I will admit when relationships at work go belly up, it can be very awkward. I actually left my first job because of it.
It's really not as bad as you're making out, I know loads of people who have done it and they're still alive to this very day believe it or not.
*edit* In the interests of a balanced argument, I'm single at the moment, and I also haven't been into an office in over two years. Go figure.