You are right that without context the article isn’t that insightful - the police (and any emergency service) is historically a job that loses a lot of people within the first few years, simply because the reality doesn’t match up to what people thought. There are also the people who just can’t do the job, for whatever reason - including
Being treated like just a number is a complaint that rings true, especially as new joiners literally are just a number and seniority is such a big thing (as it is in any organisation where everyone is serving for decades). Probationers are deliberately given the tasks they need to learn to do properly, and often these are the worst jobs, the ones where they get to understand what the organisation has to do.
That said, destroying bits of uniform isn’t and has never been “banter” - it’s clear bullying, and given how extremely cliquey some places can be it’s not surprising it goes on, but it should never be tolerated.