Could it be that melamine is wrongfully accused?

I did a further reading to do justice to this case in my mind. I also read a United Nations Environment Programme report that shows the low toxicity nature of melamine in foods. I am not a chemist and I will not pretend and interpret the data there. However, the Conclusions and Recommendations says

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Quote:

Environment:

The toxicity of the chemical to aquatic organisms is low. PEC/PNEC ratios are below 1 when based on realistic worst case conditions and on monitored concentrations. Therefore, melamine is currently considered of low potential risk and low priority for further work.

Health:

The toxicity of melamine is low. Repeated exposure resulted in urinary bladder stones and other lesions of the urinary tract. Bladder tumours occured only in male rats after prolonged irritation of the epithelium by the bladder stones. Melamine is not genotoxic. The exposure of workers and consumers is low. Therefore, melamine is currently considered of low potential risk and low priority for further work.

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I went to section 4.2.2 of that report that dealt with repeated dose toxicity and it goes,

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Qoute:

Six studies with rats, oral administration of melamine with the feed and dosing periods of 14 days to 3 months are available. Additional studies with mice and also rather old studies with intraperitoneal administration, and rabbits and dogs were also reported. Summarised findings of the different studies are: Depression of body weight gain and elevated water intake were observed at higher doses of   ca. 500 mg.kg-1.d-1. The target organ system is the urinary tract. Melamine has a diuretic effect, it produces urinary bladder stones (urolithiasis), hyperplastic epithelial changes of the urinary bladder and calcerous deposits in the proximal kidney tubules. In mice ulceration as well as hyperplasias of the bladder occurred. Changes in the urinary bladder were noted in the studies depending on the dose and the species used. A GLP 28 days study in rats ( 19 ) to evaluate urolithiasis indicated a dose dependent incidence of urinary bladder calculi and hyperplasia.The rat and especially the male rat is more susceptible than the mouse.

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If this is the case, does it mean that the guilty companies could have added such a large amount of melamine in our milk that it has become toxic?