As a young RAF airman my first overseaes tour, in 1961, was Malaya where draft Tiger Beer was consumed and the same discussion on preservatives frequently took place. The never proven opinion was that formaldehyde was an additive. Seems like urban myths have longevity.
Then, the Tiger brewery was in Singapore and transporting keg beer 500 miles northwards by truck in the sun coupled with external storage more likely affected the beers flavour.
Also on tap were the Aussie beers Swan and Emu. I can't recall those being criticised.