As far as I am aware, this is true in Ohio***. At crosswalks, pedestrians have the right of way the moment they step onto the crosswalk - though of course you are supposed to also make sure that by stepping onto a crosswalk you are not causing a hazard (so in other words, don't step on when there is a car coming up fast enough to cause an accident if they suddenly stop for you).

The exception is if you are at a crosswalk with a signal that indicates to NOT cross, then cars have the right of way (or at the very least, you won't catch me attempting to "test" otherwise). Though again, as a driver this doesn't give you permission to just plow through someone whose already crossing if you had the ability to stop safely.

*Right-of-way laws vary everywhere and are not universal (and are very specific - the places I've seen/been at generally indicate that you have to be actively on the crosswalk to have right-of-way, cars don't have to yield/stop to wait for you to step onto and begin crossing), what @[email protected] can be true for where they live, yet it could be false where you live.

**They are also complex sometimes, for example here in Ohio I believe at marked crosswalks you technically only have right-of-way on your half of the crosswalk - if someone coming the opposite direction makes a right turn onto your crosswalk and you're not on "that half" yet, then you are supposed to yield for them.

What it comes down to is, what is true and false regarding right-of-way laws is incredibly specific on context and where you are, which will explain why you're seeing some people say this, and others who aren't.

However, what is generally false is the assumption that pedestrians always have the right-of-way everywhere and anywhere.