The simulation suggests it could have happened that way. That doesn't translate well into that headline. (Given the domain name, a person might hope for better.)
Impact hypotheses are a popular type of explanation. Some may survive actual exposure to evidence, and eventually become theories. This is quite an old idea (as is the idea that the Moon impacted the Earth); maybe one day it'll pan out.
Until then, it'd be great to see fewer hypotheses in 'Science News' headlines ... and more evidence.
Axial tilt is sometimes defined such that 0° is when the orbital and rotational axes align, including direction of rotation; Venus has a tilt of 177° by this standard, because of its retrograde rotation compared to the majority of the planets.
Possibly because that would explain its rotation being the reverse of the other planets(except Venus). If it started rotating the same way as the other planets and were rotated 82 degrees, it would still be rotating in the same direction as the other planets, where as by rotating 98 degrees, the rotation is reversed.
if something is rotating clockwise with respect to surroundings. let us say,
and we were to then turn the object 180 degrees in a plane perpendicular to its rotation, the result is an object that is now rotating COUNTERCLOCKWISE with respect to its surroundings.
In summary, an impact with a another rotating object and transfer of momentum is not the only way. the object could have undergone a pole flip.