This stuff is symbolic of how far we have gone from even basic human decency. Some might blame Trump and his followers, and they certainly have shown their lack of class and decency. But the problem started long before Trump and his fans. I would say this country went downhill when prayer was banned in public schools. Sure, there are decent non-Christians, atheists and agnostics, but it seems from that point forward, America lost any sense of morality. And it appears that loss has accelerated in recent years.
I don't like McCain either, but I don't wish death on him. When a person is ill, dying or dead, it's time to put away the animosity and wish him well. Or if you can't do that, just say nothing at all.