Jack- The 2 point hitch in your link only provides friction at the point where the bars touch the "L" brackets on the trailer. The spots in the hitch rotate freely in that style; in fact the guide will probably tell you to lubricate those spots.
In a 4 point hitch the connecting spots on the hitch also act as friction hinges, so both the contact point on the "L" brackets and the connecting points on the hitch act as friction points to fight sway.
https://www.etrailer.com/Weight-Dist...EQ37100ET.html
check out the pictures in that one where the bars connect... Those provide 2 more points of resistance. Edit: This is the same hitch you also posted above.
I had an Equalizer with my old rig and it was a good hitch system. I also recommend it.