But your tax bill doesn’t go up 5%.

Ok, let’s get this close to real numbers. The cited tax brackets don’t exist, so I’ll go with the 24% to 32%. So if your earnings are 1 dollar into the 32% tax bracket, you are going from AGI $191,950 to $191,951. Your tax bill at $191,950 would be:

$11,600 * 0.10 +
$35,550 * 0.12 +
$53,375 * 0.22 +
$91,425 * 0.24 
---------------------------------
$39,110.74

And your tax bill at $191,951 would be:

$11,600 * 0.10 +
$35,550 * 0.12 +
$53,375 * 0.22 +
$91,425 * 0.24 +
$1 * 0.32
--------------------------------------
$39,111.06

Your tax bill goes up by a whopping $0.32 or 0.01% by earning that extra dollar, meaning you still got to keep $0.68 of that dollar. When they say that dollar would cause their tax bill to go up a lot, that’s pretty much exclusively owing to the misconception that people assume their tax bill would have gone to $61,424, so in the misconception that dollar would have cost them $22,313.