Bonnie, problem is that the Romans were only the ones doing the dirty work for the local establishment. The reason the Romans did so well in establishing an empire is because, like the British empire after it, they devolved power to the local rulers (or at least to the local rulers who'd give tribute to the empire). In day-to-day matters, the Romans didn't care - in fact the Roman empire was famously tolerant of different religions, and one rogue preacher wasn't ever likely to cause them any problems. But it was a big deal for the local politicians, because they could see their support vanishing. Like Protestantism moving against Catholicism 1500 years later, a grass-roots movement threatened the stability of the overbearing established political organisation.
So Jesus was only hauled up before Pilate on the say-so of the local political elite, who happened to also be the local religious elite. Pilate's hand-washing was in rejection of official Roman involvement in the decision. If we're quoting Bibles, remember that Pilate gave the crowd the option of releasing Jesus, but the Pharisees' agents in the crowd called out for Jesus to be executed.
But none of this makes the Bible, or the song, anti-Semitic. Jesus wasn't anti-Jewish, he was anti-Establishment. Gerry's argument is the same specious argument used by supporters of Israel when they say that by criticising Israeli actions in Gaza, their critics are anti-Semitic. When there's an official state religion, it's essential to differentiate between actions which are based on religious doctrine and actions which are matters of state politics, even though the same people may be making those decisions. Failure to make this distinction is at best naive.
Assuming that the Bible is an accurate representation of events, it's blindingly obvious that a few Jewish people 2000 years ago were responsible for the death of Jesus. It's also blindingly obvious that the Jewish religion had nothing to do with this fact, since Jesus's aim as a fellow-Jew was to move Judaism from empty sophistry back to an appreciation of the basic principles behind the religion. And it's equally clear that none of this has any relevance to Judaism past, present or future, nor to any Jews who weren't directly involved in the event.