If we start with the assumption that harrasment cause suicides then that argument means that it's ok to harras people as much as others do on average.

Obviously there is other causes also. But the base principel is a very shaky foundation to build a legal framework on.

This is, in essence, the argument that the CEO made, during the crisis and at the trial. He kept saying (paraphrasing here) that there was no statically significant increase in the rate of suicides, and because the company was so huge it was bound to have employees killing themselves from time to time, regardless of what management did or didn't do. According to him, the whole affair was a pure media campaign orchestrated by people who disagreed with his management of the company.

The incredibly insensitive delivery of this argument cost the man his job years ago. The immense grief of families and coworkers, the fact that the suicides appeared to be work-related (and sometimes even happening at the workplace), the scathing reports by medical inspectors seemed all irrelevant to the dude, who basically just looked at this as a statistic to be managed. His lack of public displays of empathy or desire for introspection was pretty disturbing.

You may want to look into Base rate fallacy

https://en.wikipedia.org/wiki/Base_rate_fallacy