Okay, I'll break it down for you.

Most of the modern Peterson-style "discourse" exists to provide a pseudo-intellectual justification for the feelings his audience already has.

Many people grew up doing a lot of messed up stuff without thinking about it, because everyone around them was doing it too. It just seemed normal at the time.

Now the same behavior they've done is being called out and this makes them feel bad. They don't like feeling bad, so they pay someone to tell them they aren't actually bad - they want to hear that they're good people and the people calling out similar behavior are just oversensitive kids and "wokes" that are overreacting to harmless workplace banter.

This is why you absolutely have pre-existing beliefs due to the culture you grew up in. Everyone does. Many of the kids that threw rocks at black children attending the first integrated schools are still alive today. Their kids don't want to think of their parents as bad guys either (hence why so many parents are trying to stop schools from teaching about the history of racism - because it makes thanksgiving uncomfortable when grandpa was one of the people that threw the rocks).

Our brains are extremely prone to cognitive biases based on a number of factors, especially how we're presented information. It's just science. Good books on that topic are "The Undoing Project" and "Predictably Irrational".

The former is an engaging read about how our brains can make flawed judgments in even seemingly simple, objective situations (like judging how well basketball players perform in a team tryout) and how two unlikely geniuses spawned a rethinking of basically every industry.

The second is an example of various studies that showed how even highly intelligent humans reliably make irrational decisions due to various cognitive biases.

For example, people exposed to a $4 price first for a new type of luxury candy bar tend to think it's worth $4, and balk when asked if they'd pay $5. People exposed to the $5 price first tend to think it's worth $5 instead. This is how impactful a small difference in how you're introduced to the world can affect your perceptions of even something that should be simple.

How you've grown up to this point will massively impact your perceptions on many, many things.