Er, that's bad logic. People have ratios over 1.0 exactly because they're concerned about their ratios. Otherwise, their good standing would evaporate quickly. Furthermore, there is no actual requirement to maintain a good ratio, it's optional. BakaBT is a public tracker, and if you don't log in, no ratio is kept. Ergo, people who log in ARE concerned about their ratios, wouldn't you agree?
The minimum acceptable ratio isn't stated, because then people will simply use *that* as their target. A ratio of 0.5 (the threshold for Power User) isn't much to ask, in a P2P community, and considering you don't have to log in at all, I don't see the problem.