There is plenty disdain for both. However ARM is (was?) gaining mindshare and starting to take even more marketshare and mindshare from Intel. Intel is a bit on the ropes right now because they can't keep up with TSMC on miniaturization and other chip technologies. I think it's popular to be against the 800lb gorilla. This deal is likely really bad for the platform as Nvidia doesn't have the greatest history for being a "nice" player in the tech world either. I think the primary fear is they will stop licensing the ARM IP to other companies and claim it solely for themselves in hopes of going even more head to head with Intel across the entire spectrum of chip technology.

I’m sure there are people who have legitimate issues with x86 and its extensions. I’m not one of them.

What I believe most people are concerned with are low power high performance devices. ARM owns that space. It would be at the very least disruptive to have ARM platforms die.

On the high end Intel CPUs in servers are very expensive. Many people on HN have expressed hope that cheap ARM cores become good enough and drive down the cost of both on-prem and cloud servers.