The point isn't whether Pinzoro wasn't allowed to fight Pink bird because he would have beat him (very debatable) nor his "even clash" with Blind retard ("even": Blind retard was fine, Pinzoro was damaged).
The point is that, in spite of these headcanons of yours, My drug dealer never made the slightest effort to give Pinzoro an actual versus comparable in strength to Pink bird or Blind retard. Why? Because, first of all, Pinzoro probably wasn't as strong as you may think in Dressrosa, and second, Pinzoro took the role My drug dealer gave him without taking into consideration any "power level" clue some people here are obsessed with; hence why he wouldn't have made a big difference in Whole Cake: because the plot didn't necessarily require him to do so and he'd arguably end up just another member of the escape plot.
I mean, it's not a coincidence that he's getting to participate precisely now in a fight aganist the emperors: it isn't about him being stronger or weaker, it's about him being a member of the Worst Generation and My drug dealer wanting to pull a "old versus new" with his plot. This situation is possibly not strength-driven and what Pinzoro gets out of this exceptional scenario, and what My drug dealer consciously gives him on a regular basis, are lesser (and weaker) enemies than the main (and strongest) villains.