Now most us are probably wondering: what can possibly be wrong with mentioning a name? Are we now going to edit the Torah to remove the names of beautiful women like Sarah and Rivkah? After all, who knows how many men have been tempted into sexual fantasies by the mention of their names? Such an approach is just absurd.
Unfortunately, we cannot end this discussion here. Because we should not immediately dismiss even an apparent “absurdity” when it receives support from a gemara – in this case, Megilah 15a. There it says that Rahav the prostitute (from Sefer Yehoshua) was one of the most beautiful women ever to live. The gemara continues as follows:
R' Yitzchak said: Whoever says "Rahav, Rahav" immediately experiences a seminal emission.
R' Nachman said to him: I said "Rahav, Rahav" and it didn't affect me.
He [R' Yitzchak] said to him: What I said refers to a person who knows and recognizes her.
According to this gemara, saying a woman's name can be enough to send a man far, far into the realm of forbidden sexual thoughts!
Additional evidence for the charedi position comes from a source that they themselves would absolutely never consider looking at (I suspect that the best evidence for charedi positions is often from such sources). That source is Mambo No. 5, a popular song from 1999. It describes a bunch of women's names and what the singer does which each of them. The descriptions of these relationships are absolutely tame – Shir Hashirim is more explicit. But the fact that there are so many of them gives the impression that we're in the middle of a giant binge of orgiastic womanizing. A name represents a personality and thus a potential relationship to you. So mentioning each of the names helps us to imagine their relationships, much more so than would a simple running count (1, 2, 3... 56, 57) of how many women the singer has conquered.
By now, we can discern two contradictory approaches. On one hand, refusing to mention women's names feels absurd, and in fact even the Torah doesn't do it. On the other hand, there is some evidence that names can be sufficient to cause sexual thoughts. How do we reconcile our two hands with each other?
The only possible resolution is to say that the prohibition on sexual thoughts is not absolute. If we were really “serious” about avoiding sexual thoughts, we would prohibit one sex from ever stepping out into the street. (I'd suggest men, since women have to go to work each day, whereas men can learn Torah equally well at home.) The stimulation of seeing a physical person is surely greater than that of seeing a name in writing. Yet nowhere, not even in Mea Shearim, does anyone propose such a standard. The logical conclusion is that we do not aim to eliminate sexual thoughts, only to keep them below a certain threshold, which is high enough that we still have the freedom to pursue our other goals in life. And practically speaking, the mention of names is well beneath any conceivable practical threshold. On the contrary, in modern society the refusal to mention names is immodest, in that in it forces us to consider sexuality, in a context where otherwise you wouldn't have thought of it.
There may also be an simple explanation for the gemara in Megilah, in which the degree of sexual thoughts caused by mentioning a name is well above any threshold we'd consider setting. R' Yitzchak said that the person who ejaculates upon saying “Rahav, Rahav” is one who “knows and recognizes” her. The phrase “knows and recognizes” here is redundant. Perhaps “knows” (or else “recognizes”) is meant in the Biblical sense – to have had intercourse with her. If such a person says “Rahav, Rahav” – repeating her name over and over, not just saying it once – one can imagine it leading to vivid fantasies. That is hardly comparable to reading, once, the name of someone you've never had intercourse with and often have never met.