But here is the horrible question I ask myself: might these ancient rabbis have known that Jesus was the Mashiach (Christ), and still done all this?
Personally I don't think so. I believe the ancient rabbis not only did not believe, but also did not want
to believe. If you think about it in a broad scope, throughout the OT we see god saving his people by wiping out their enemies. In other words, the Israelites understood power, plain and simple. When they were in a tight spot, they would ask God to wipe out their enemies and be done with it. They would rejoice, worship God, etc., but as many people did they forget. They resumed sinning and thus God let their enemies have their way with them. The Babylonians, Persians, Romans....a lot of enemies there. For a long while the jews believed that God had turned their back on them since hadn't been smiting their enemies with the frequency they were accustomed to. Of course the Son of David was prophesied to deliver them to their promised land, and you can bet all the jews back in the day were on the lookout for some sign of divine smiting.
So here you have all common jews who have read of the Son of David returning, thus they're expecting someone to show up with God's power ready to smite any and all in his path - again, they are used to understanding power from the perspective of smiting others. But when Jesus shows up claiming to be God and not
smiting their enemies as they expected, well you can understand they were probably pretty upset because they're expecting divine smitation and this guy comes around preaching love.
The problem here is (and this is my opinion) the jews were incredibly close-minded and didn't understand that the Son of David had returned. Perhaps God understood that he couldn't keep intervening in their affairs by smiting everyone so a different approach was necessary, a message of peace and love - a new covenant. Look at all the miracles Jesus performed. Raising Lazarus from the dead and rising from the dead himself....what greater power could there be? And still the jews did not understand; there are many who still do not even today.
The rabbis back then undoubtedly did not want
to believe it because it as simple as the fact that they wanted to retain what power they had among jews. When Jesus comes along telling us of the new covenant, well, that would pretty much put them off to the side but they did not understand there was a greater destiny here: their promised land was being delivered to them in the form of the church.