I pity the parents in the sense that they'd rather have a dead child than a happy, healthy transgender child. I find them more despicable than anything though. Aside from the things the parents were saying to their kids, in Leelah's case at least, not sure if Zander was also put through conversion therapy, they also paid "therapists" to verbally abuse her. I don't mind people who have religious viewpoints, I went through six years of Catholic school, I know religion's not evil, it just bothers me when that's used as a way to make your child feel terrible for coming out to you about who they really are. They're both incredibly brave for coming out at all, I can't imagine what kind of slap in the face it is to be immediately rejected after that. And the fact that both sets parents still misgendered their children after they died is really heartbreaking.
I don't believe Zander expressed any worry about transitioning (if he even planned on transitioning later on) but I also found it really sad Leelah believed she wouldn't be able to successfully transition after age 18 as that's not true. I'm sure it helps to start when you're younger (going through the wrong puberty probably makes what gender dysphoria a trans kid has 10x worse and that's when the secondary sex characteristics kick in) but that doesn't mean you'll look odd if you transition later on. Transitioning's about making yourself happy. I can understand her fear of transitioning later on though as transwomen are often the victims of violence and not passing could potentially put one in a dangerous situation. But that doesn't mean you won't "look the part" if you start hormones later on. Isabella Bennett from Steam Powered Giraffe is a good example of this, she started hormones about a month and a half before turning 29 back in August, and she looks great if I do say so myself.
Society's definitely taking steps toward becoming more trans friendly though there still needs to be a ton improvement. As Leelah stressed in her suicide note, transgender stuff (and just better sex education and LGBT stuff as well) needs to be taught in schools, the earlier the better. Children are in general more accepting than adults so that'll eventually lead to an overall more accepting society and environment for transpeople and it'll help any young trans kids figure out that there's not anything wrong with them. More shelters for trans youth would probably also help so trans teens can get out of their unhealthy home environments and kicked out trans teens will have a safe place to go. There's also the whole public restroom thing with how trans people shouldn't be nervous to use public restrooms. Nobody's ever exactly thrilled about public restrooms but being nervous about using one out of fear that you might be looked at funny, questioned why you're there, get a rude comment directed towards you, or even physically hurt just sounds awful.
As you said, it's not an easy fix. There will always be people who are unaccepting and ignorant that'll want to hold the whole thing back and keep society from progressing to a trans safe place. But at the very least, awareness of what trans people (especially trans youth and their unsupportive, occasionally abusive environments) face on a daily basis is going up and that's helping. It's not going to be an overnight change but slowly but surely it's happening and at the end of the day that's all that matters in my book; that society's progressing and not regressing. Considering how fast same sex marriage is getting legalized and more accepted hopefully protection and support of transgender lives will follow in suit of that c:
I feel like this is just me spouting off my very strong opinions on the matter. I tried to keep this factual in one sense or another but I apologize if this comes off more opinionated than I intended it to