I always get the feeling that the older you get the more tolerant you become with regards to kids.

The reason might be that, as an adolescent, you are in a period of life in which you want to be an adult and prove yourself as an adult, which means you'll have to set yourself apart from kids.
Kids enjoying your favourite hobby doesn't help in that matter.
So it's either giving up the hobby or avoiding kids at all costs.

I remember the time when I was under 20 and simply hated those "kiddos". I hated being around them. Their excitement annoyed me and they mostly weren't a tactical challenge. I used to play in group of peers that was approximately 1-3 years younger than I was.
Going to an official tourney was always kinda disturbing. Also, there was no store around. We used to play at our homes, sometimes even without a table.

Now, I'm an adult. I'm almost 30. A teacher nonetheless. I enjoy being around kids and working with them is the best experience of my life. Still, I got into the hobby when I was 14. I simpy can't support a policy of children under 12 to join the hobby. Sure, there might be exceptions but those are quite rare.

Oh, and just a little political statement from me:
I have no respect for people beating or even flogging their children.
My mother used to beat me for bad grades. Her beating didn't improve them.
And they certainly didn't improve me.
I have no respect for her today.
If you want your children to love and respect you when they are finally grown up then I recommend loving and respecting them while they still grow.

Cheers!