Apologies if this is a bit of an info overload, but I don't think it's clear what route they took from what I read
Some of it is just luck and logistics of who is where in the system. Traditionally there is very few young babies, because often a birth parent has to noticeably fail, be tried with support, and has multiple opportunities to appeal etc before a child has the right paper work to be placed for adoption which all takes time. If I remember correctly in this case, the birth mum had repeated kids taken away so it may be that some of that was done while he was in utero but I think he was about a year old when he was placed which is a fairly normal entry point.
Lots of the youngest children in the system are under foster to adopt, basically where they strongly suspect that the child will be placed for adoption but the process isnt complete. This means you aren't an adopter to start with but a fosterer so there is a possible chance the baby doesnt stay with you, you might have to facilitate birth parent contact etc. There's a real push for adopters to do this because it lessens placement changes etc, its fairly common.
We were given lots of profiles to look at, and some profiles are more popular than others. I imagine with Prestons back ground that he may have some concerns in his profile which may put others off. For example babies where there is a higher likelihood of delay, where mum has used drugs and alcohol, where there's genetic issues possible or where fas is possible.
Ultimately there are babies in the system but they tend to enter and exit quickly. I know a few adopters who by chance ended up with fairly young babies via the traditional route, and even more by the f2a route. There are babies, the matching of them just can be more competitive. When we were adopting, girls where more in demand, and it was seen as more of a risk to take a 12 month old than a 2 year old because there was less known about them
In my experience its not that gay people skip a queue or that their experience is any different to the rest of adopters. I saw plenty getting declined, getting older kids etc