I don't really understand why they use real source addresses tbh...
Obviously trading on my internationally renowned good name.
As long as it's just spoofed I'm not too fussed. My escutcheon may have been blotted in the block list of some Russian spambuster nannyware, but I can live with that.
If you have an email address visible online then chances are it will happen. I was once worried it may end up with my address black listed but apparently the black listing people are smarter than that!