If they'd manage to convince other ISP's to drop any BGP sessions with Russia, it probably means a separation of Russian internet from the world, and that would probably make more harm than good in the bigger picture.
The fact is that the people of Russia need to feel incredible pressure. Their lives must become incredibly difficult. Unbearable even. It's the cleanest way out of this.
Mmmmkay. Bit much on the blowing up the house to put out the fire. Personally, there are still a few nuts that deserve to flourish over there. SciHub being one of my chief concerns.
I am literally in the middle of making another backup of my copy of Scihub, this time to LTO tape.
If Russia feels too much pressure and goes into complete isolation from the West there is nothing too lose anymore and the conflict can easily escalate beyond Ukraine.
US/Europe want to avoid this due to the huge disruption it would bring economically (gas shortages etc) and the end of any hope for a diplomatic resolution.
I'd personally support more measures, but it's not as clear cut as one might assume.
We still have to share a continent, and pushing Russia into the arms of China can have huge long lasting ramifications.