Before I moved to Texas, I never slowed down during rain, didn’t need to.If you're scared, pull over and wait.
But the huge downpours here had me slowing down to 40-50mph a few times. You simply cannot see far enough, plus the water doesn’t drain fast enough in some places and there are a lot of big puddles on the highway. Going fast over them is a guaranteed hydroplane situation.
Pulling over is not smart either because with such low visibility, especially at night, someone will most likely rear end you.
Nothing to do with being scared. Common sense should prevail over bravado for most adults.