The standard utilitarian argument for pursuing knowledge, even when it is unpleasan to know, is that greater knowledge makes us more able to take actions that fulfil our desires, and hence make us happy.

However the psychological evidence is that our introspective access to our desires and our ability to predict what circumstances will make us happy is terrible.

So why should we seek additional knowledge is we can't use it to make ourselves happier? Surely we should live in a state of blissful ignorance as much as possible.