You are missing the point. I can very easily send you an email from or from your own email address or even from if you would like me to. It won't REALLY be from those addresses, of course, but to the level that you looked to see who this was from, it will certainly look like it is.
Just like eejit's email looked like it was from Neteller and all the ebay ones look like they are from ebay. I promise you though, those sites are not trying to scam you to get your log in info - they already have it.
