That's because they're not even remotely comparable things, as you note. Afghanistan is a security operation, not a traditional war. There's no draft, thousands of US soldiers aren't dying in Afghanistan. Even the cost is a modest fraction of the total US military budget.
There were 15 US casualties in Afghanistan in 2017, and 14 in 2016.
There were 15 US casualties in Afghanistan in 2017, and 14 in 2016.
That's not a war. That's a security operation.