That seems a little too short-sighted to me...: "evil" thoughts do not automatically make someone a bad person. I think. On the contrary: the realisation that good people are also capable of negative and criminal thoughts - and yet remain good people - should put your objection into perspective. If thinking was only okay in socially predetermined ways, there would not have been many innovations, but also not many social upheavals.

In general, I think that nowadays there is a need for more freedom and less supposed security. As far as freedom of thought is concerned, it should definitely be inviolable!