Why is harsh to call someone who spent time in jail, a crook??
It's harsh because your are insinuating that every person who's spent time at her majesty's pleasure is a crook for life, regardless of whether they've been rehabilitated and never go on to commit another offence in their lifetime. A brilliant example of prejudice served up there.
No, we're talking about a single person, not "every person who's spent time at her majesty's pleasure". Plus, I asked a question - how is that prejudice? I would consider it
reasonable to be called a crook, as he has a previous conviction.
Prejudice would be saying the son of a convict is bound to be an offender... not sure you seem to grasp the meaning of the word.