It means showing people not living in a monogamous stable relationship dedicated to upbringing of their kids, that it is "normal". I'm not a homophobe, so I guess I won't fuck off, asshole. I have nothing against gayness, I am actually a bit bi, also unmarried. However, I know that if everyone lived the way I do, this society would be MUCH, MUCH, worse off. Therefore I would not advertise my lifestyle and tell people it is okey, and they should live it.
Being gay is not the issue, the issue is people not marrying or having kids and dedicating their lives to it because they see other people not doing the same. Thinking that's normal is good for the individual, but not good for a society. US is doing fine in that regard, but Russia is not, population is declining, people are not marrying or having kids as much as they did before, and lifestyle propaganda is one of the few things the state can do.