Why do parents train their children to misbehave?

Because they don't want to put in the time and effort to raise them correctly. They're too selfish & would rather use the children as a decoration to embellish their lives rather than see them as a treasure & their future. They teach them to misbehave because they think it's "cute" when they're younger, not realizing that the kids will grow up thinking that it's ok. Smack talk may be cute as a toddler, but it's far from cute when your child is disrespectful when they get older.