Census data is in the public domain because it is produced by government employees paid to collect and compile it. If someone resells it, it is now available free. It can never be copyrighted. Because of the potential of abuse it is embargoed for seventy-two years, so it is not available to law enforcement, the military draft, immigration, tax authorities, partisan politics, or any commercial purposes.
In general I have found that elderly people are delighted to be shown as children. But as a rule the data is shown after careers are over. You will not find that someone has been a physician or attorney before the person is deceased.
Yes, I have seen embarrassing personal details such as imprisonment... but as a rule this is almost invariably of people now deceased. Crime is a choice, and a bad one. Imprisonment can appear on a Census record, but almost never of a living person. Take care in assuming things. People have taken the rap for others, and people have been wrongfully convicted. But do the crime and do the time -- and being able to trace a lost relative might be interesting. What harm can you do to a convicted horse thief from the 1870s? The fellow is dead.
It is true that on occasion you will find a census record that shows someone as a prominent scientist, creative person, academic, or politician. Most people do not have such interesting lives.