I don't think any modern academic writing guide recommends this; almost every piece of advice I've seen tries to emphasize writing in the active voice.

You don't have to write in passive voice to be rigorous; I'm guessing the OP was talking about this lack of rigour.

I thought the tide had shifted towards active voice as well. However, a year or two ago I looked it up and some well known journals still preferred passive voice.

Here's an interesting recent paper that found that roughly 30% of papers are still in the passive voice (admittedly, I was expecting a higher percentage).