Yes, Haber's right, but she doesn't go far enough when she writes "Such holiness was associated not only with the temple but also with the biblical scrolls that were read on the Sabbath, and perhaps even the synagogue in which the Torah was read and studied." She left out other daily holy activities, like praying. (I haven't read her article. I'm just going by what you've quoted, Rafael.) The hemerobaptists had a problem with the Pharisees because they would say their morning blessings without first purifying themselves by immersion.
He then points out, in a later comment, that the Pharisees weren't advocating prayer without purification; the debate concerned precisely the means of purification (immersion vs. hand-washing).
Poirier's focus on prayer struck me as interesting, in part because I myself had never considered the purificatory requirements prior to prayer. Of course, it makes perfect sense to include prayer here; notice, at a very basic level, the way prayer and sacrifice (which happens in the Temple) are intimately linked in Isa 56.7 (cited by Jesus in the Temple incident) as well as in the phrase "hour of prayer" (see Acts 3.1). I think both of these uses of prayer (Heb. תפלה; tĕphillâ; Grk. προσευχή; proseuchē) equate this word with sacrifice, which should tell us something about an understanding of prayer in Second Temple Judaism.
If sacrifice in the Temple could be referred to as prayer, then it follows fairly naturally (though not automatically) that prayer in other venues (e.g., the synagogue) would require purificatory rites. So I was particularly interested to note that Haber does indeed move in the direction Poirier mentioned. In her discussion of Diaspora synagogues Haber suggests, "It is possible, however, that the water was used for ritual ablutions prior to prayer or the handling of the Torah" (71). Then, on the next page, she cites a passage from the Letter of Aristeas, which deserves mention here:
Following the custom of all the Jews, they washed their hands in the sea in the course of their prayers to God, and then proceeded to the reading and explication of each point. I asked this question: "What is their purpose in washing their hands while saying their prayers?" They explained that it is evidence that they have done no evil, for all activity takes place by means of the hands. (Aristeas 305–6)
Haber goes on to explain, "In this passage, hand washing is associated with both prayer and the handling of Scripture" (72). Given the frequent reference to synagogues as "[houses of] prayer" (προσευχή; proseuchē), and the evidence Haber evinces to suggest that "the synagogue building was regarded as sacred from an early period" (73), the link between purity, purity practices, and prayer seems especially secure.
One more question: Poirier, in his most recent comment, notes the Pauline exhortation to abstain from sex (only) for the sake of prayer (see 1 Cor 7.5). I'm not sure if I'd make anything of this particular gospel tradition, but in light of the connection between purity, space, and prayer, should we understand Jesus' instruction to pray in secret (see Matt 6.5–6) in terms of debates about purity? In other words, does the Matthean Jesus suggest prayer in the synagogue and on street corners, in the hands of "the hypocrites," suffers some sort of impurity?