It's a consequence of the reversibility of orbits that anything that free-falls from a near-interstellar distance. Take the Vis-Viva equation, the formula for the velocity of objects in Keplerian orbits/trajectories:
$$v=\sqrt{\mu\left(\frac{2}{r}-\frac{1}{a}\right)}$$
Where $r$ is the radial distance, $a$ is the semi-major axis, and $\mu$ is the standard gravitational parameter.
When $a$ is very, very large compared to $r$, things start to look like this:
$$v=\sqrt{\mu\left(\frac{2}{r}\right)}$$
Which is the formula for escape velocity.
So basically, almost anything falling from the Oort cloud to the inner solar system is going to be scraping the underside of escape velocity in the inner system, at minimum.