On a webpage on nude beaches in Europe, which I will not link here because it contains a photo you probably do not want to see, it lists of nude beach in Venice as in Isola del Morto island, near Eraclea, not on Lido. As I have been to Lido several times, I recall that Lido, like just about all European beaches, probably has nudity but not much. One really has to look for it to notice. Bon voyage.
Hi Vikram (and welcome to Slow travel!) I had never heard about the Lido beach being a nudist beach (usually nudist beaches in Italy are very tiny and secluded and Lido has many different spots of beach) so I had a look at the internet and I discovered that there's a small nudist beach in the southernmost area of the Lido (south of Malamocco) called Alberoni.
I think the mention of nudity probably refers to women going topless. And yes, there are women on the Lido beach who sunbathe topless. But I think you would be hard pressed to find an Italian beach where there were no topless female bathers. If I recall correctly, it's not viewed as such a big deal in Italy while I respect other cultures might think differently.
Alberoni is considered a gay part of Lido, but by no means exclusively gay and certainly not an exclusively nude beach. But JS explained better than I: Vikram, everywhere you go, in the beaches in Europe, you are likely to see women topless. This phenomenon is not confined to specific sections of beaches and is therefore difficult to avoid. Then there are specific nude beaches which can be avoided. Lido has the former guerilla kind of nudity.