Doctrine introduced entity repository class as an object finder where you can keep methods to find and fetch entities. To make this process even easier it provides methods to create and run DQL queries. As an alternative, instead of writing DQL you can use query builder. And that was exactly what we did in most cases.
Inside our repositories many methods did similar things: create query builder, apply criterias, set specific order, perhaps pagination and fetch results. Besides of course methods to count items, get statistics, apply custom hydration and so on. Basically, we placed there everything entity related but that was not its responsibility. We saw other people using absolutely the same approach in their applications. But why it could be wrong?