Why do people do things that clearly aren’t a good idea?

I have recently been diagnosed with obsessive compulsive personality disorder, and I find it causes me to have rigid thinking at times. I am trying to see things from other points of view but I have trouble sometimes.

The example I have at the moment is people giving their newborn rice cereal in a bottle. All the evidence is clear that it can be dangerous, “foods” shouldn’t be given that young, and it doesn’t help with sleep.

So in my mind, I can’t understand why anyone would think that’s a good idea. Yet plenty of people still do it.... knowing all the reasons they shouldn’t. (Yes I know medical needs such as reflux are an exception).

So can anyone help me understand why people do things when all the information is clear they shouldn’t? Please don’t get stuck on the example I’ve listed, and feel free to answer the question more broadly so it can pertain to other examples as well.

I mean no disrespect, I simply do not understand why people do things that clearly aren’t a good idea.