How does dressing up as a baby suggest to anyone that the people dressed up might be paedophiles? The comment was all about context (deliberately created by Reelfountain) and that context is to suggest that the men are gay (an assumption in itself) because they are attending an LGBT pride march. It's exceptionally common, even in this day and age, for homophobes to rely on anachronistic tropes of gay men as paedophiles; gay men as perverts, gay men as immoral, gay men as predators. They are all homophobic triggers that attempt to spread hatred of LGBT people. Homophobes use them because they work. They work because we still live in a homophobic society.
A guy dressed up as a baby, with a pacifier for Halloween. Is he more or less likely to be thought of as a paedophile? The common sense answer is less likely, in this context, he would just be an adult having fun, being silly. Just as the three men at Pride were doing but were castigated for.
The only reason that children were introduced to this comment was a further attempt to brand LGBT people as predators, LGBT parents as irresponsible and as 'bad' parents. This was confirmed by the comment "children should not be indoctrinated with diversity". It was just more, thinly disguised, gay bashing without any thought, or care, for any children anywhere as evidenced by the comment "2 gay kids, unlucky".
I think parents whether they are LGBT or straight have a duty of care to their child(ren). Parents in attendance at Pride in London, with their children, I have no doubt believed it to be a safe, healthy and welcoming space for their child. I would take my child (12) to events such as this without any reservations. I see it as a celebration of a long fought battle. I don't believe as was suggested that 'gays' prefer the shadows or that they should be forced into those shadows.
You mention hypersexualised. As I would take my child to Pride in London I would also take him to The Nottinghill Carnival. This is a highly hypersexualised environment but it's accepted as such because, in this heterosexist world in which we live, woman and men walking the streets scantilly clad is accepted as flamboyant, colourful and fun. LGBT people do the same, or similar, and they are accused of being sexual predators.
I think all children sexually mature at differing ages and that as a society we must do our level best to prepare them for the world that awaits. Given the overall sexualised world in which we live children are developing into adults at a younger age. My preference is that children are introduced to the issue of relationships in year 1, primary. By discussing the topic gradually through their education children 'should' feel less enbarrased and uncomfortable when the topic comes to sexual relationships. I would want my child at any age to have the skills to tell me if had been touched-inappropriately or that he felt uncomfortable with someone and was then able to explain why. I want my child to enjoy life but I want him to be aware of the dangers.