That’s actually a myth. Global cooling was a small minority of published papers in climatology at the time. They were many more papers discussing warming.

Source: https://ams.confex.com/ams/pdfpapers/131047.pdf

P.S. I learned this watching the excellent video by Veritasium on climate change misconceptions:

https://m.youtube.com/watch?v=OWXoRSIxyIU