Should Language Be Used to Justify Coercion?

Should language be used as a tool to justify the coercion and imprisonment of those who have not committed crimes?

Mental illness is not a real physical illness. If it is, then it is primarily a brain illness and not a mental illness. What is important is then a matter of how you define illness; is a it a specific biological phenomenon or is it an a subjective term that can be applied to anything and everything that one desires (most often disapproved of behaviors) for any reason at all? For example, homosexuality was described as a mental disorder in the past; and the defining the desire to not be a slave as illness was once attempted (drapetomania). Will medical language related to illness be used to try and treat genuine biological illness only or will it also be used as a tool to oppress and justify psychiatric coercion?