I think this is more a matter of politics than technology. That beam weapon is standard Asgard technology. They were reluctant to give it to humans for fear it might be dangerous in the wrong hands.
To really understand this, you need to have watched the spinoff show "Stargate: Atlantis". When the first Asgard-human ship shows up to the Atlantis city in the Pegasus galaxy, it's revealed that the Asgard gave humans the advanced engines it would take to travel to another galaxy, but they refused to give them any advanced weapons. This is why all weapons fire you see are from inferior rail guns developed by humans on Earth. (Only reluctantly, when asked, did they allow humans to beam nuclear bombs to attacking Wraith ships.)
Also, remember that the original Asgard-human ship was not even given to humans on purpose. It was a really old ship found crashed on Earth, which is why it originally didn't even have the engines it would take to travel to other galaxies.
The Asgard generally did not want to share technology with humans.