What would cause me to be "un rehireable" at a job?

A little less than a month ago, I was let go from my job at Chipotle for being relatively slow. After I was let go, the manager was transferred and the restaurant got a different, much more experienced manager (the previous one had been manager for less than a year, and was pretty much winging it the whole time). The reason I was originally slow, was because the old guy (we'll name him Chris) forced me to do a certain task all on my own, which I could never finish. The new guy (we'll call him Bryan) makes everyone help because he understands it wasn't a quick process. I thought this was really unfair, because if I had worked under Bryan's policies, I would never have been fired. I went to talk to Bryan and the supervisor of the area (we'll name her Lisa). I explained to them my situation and how I found it unfair, and they agreed with me (Lisa even saying the restaurant had a lack of leadership). They said they would hire me again, IF I was rehireable. But, why would I be unrehireable? Is there certain reasons to that? tl;dr I was fired unfairly and will get my job back if I'm rehireable.