Anxiety stems from a bad upbringing.
Anxiety disorders can result from various aspects of childhood including “bad upbringing”, but to imply that is the only cause is ridiculous.
Anxiety is a natural reaction to a perceived threat or danger. So where do we learn that something is dangerous? Easy answer….Life experiences. Some life experiences where we learn inaccuracies about danger can occur in childhood, for example if a parent is fearful then the child can learn similar fears. If a child is abused, physically or emotionally, for taking childhood risks, then the grown up child may have anxiety issues related to risky situations.
Other anxiety disorders can develop during adulthood and have no connection to childhood at all, for example stemming from various traumatic experiences such as serious injury or death of a child, military combat, or natural disasters.
Anxiety can be complex and to make an overly simplified judgement as to it’s cause is irresponsible and dangerous.