No, I'm not a troll, just a guy who's pointing out the troll. This is the troll post you made.
You've been pounding this point home for a very long time. You have been proven completely wrong by numerous expert posters, a few of whom either modeled the stroke with computer software or made a rather elegant little tip-travel charting device. Now you are trying to link bridge types with stroke types, only there is no connection here. Either type stroke can be made with either bridge. I do it all the time.
FWIW the closed loop does nothing to maintain a straight-line stroke. Nada. The fulcrum is beneath the stick in either bridge type. A real piston in an internal combustion engine has straight sides of some length, with extremely tight tolerances to the cylinder wall. This is what keeps the piston moving in a straight line (and not the connecting rod assembly like you believe to be true). The hand, even with the strongest of grips, is neither hard enough nor tight fitting enough to force the cue movement into a linear direction. You are deluded if you think differently, and 30 seconds at a real-life table should be all you would need to convince yourself that this is true.