Why do some drivers slow down, or stay slow, or even stop, before merging onto a freeway from an interchange or onramp?

Any adult driver who has observed physics (and who paid attention in Drivers Ed) realizes you are supposed to SPEED UP when merging onto a freeway from an interchange or onramp. And you’re supposed to do so ½ way around the curve (if it’s a curve) or IMMEDIATELY if it’s just a straight ramp.

Yet, a small but significant percentage of adult drivers prefer to slow down or “creep” onto the freeway.

Why are they doing this? If you have anyone in your own life who does this, will you ask them what kind of logic and rationale they are using? Even though they’re wrong in the most stupid of ways, I’d really like to know what’s going through their minds.

Don’t they realize that by slowing, creeping, or stopping, they are LOSING momentum, which could be used to make a safe merge?

I’m talking about typical interchanges and onramps. I realize there’s a few onramps in the South where you’re supposed to stop. Not logical planning, but that’s how they were made. And I’m not talking about when the traffic is jammed, either.