Strong arguments indeed. However, I'd like to point out a few things.
1) You're confusing "arab" with "muslim". Perhaps how I worded the last argument referencing this doesn't help you here. "Muslim" is the religion. Anyone can be a muslim the same way one can be arab, and the two of them are usually, but not always linked (an arab can be an orthodox catholic and a redneck could be muslim). Therefore, to reject a muslim person, the only way is doing some "research".
2) Telling the employer you're married is one thing; the employer actively eavesdropping my cyber conversations is another. In the first situation, the employer is passive; you told him because somehow you wanted to. In the second situation, even though you didn't tell him, he decided to "research" by himself and found out about you.