How are you defining light? This is a request for clarification.

If you mean light beers in the sense of the modern marketing term, that didn't exist until decades after the end of the Victorian period.

If you mean lagers over ales, then no, there's no truth to it. Lagers were hugely popular around the world at the end of the Victorian period.

If you mean adjuncts, beers where rice and other nontraditional grain were added, Budweiser being a pretty solid example, then the answer is still no. These were also popular and didn't have any sort of stigma against them.

If you mean the sort of watered down beer made in the prohibition period, we're now outside the Victorian time frame, but also no because that's just what was there.

If you mean something else, let me know and I can address it. I've not been able to find any references to lighter forms of beer, however it's defined, as indicative of someone being gay.

Anyway let me know. Also I'm curious as to where you heard this, and why specifically relating to the Victorian period.