Why should it just be for 'lovers'?
Can't things evolve? The way people celebrate easter (for example) has evolved too.
Why does it bother you what other people do so much? If you don't want to for your kids, fine.
I don't think it's that unusual. I remember as a kid we all made valentines cards in art at primary age and gave them out to our friends.
Valentines Day is a fairly modern tradition anyway, so it's bound to change.
According to Wiki Valentine's Day has loads of traditions around the world, not just an american influence. E.g. , "Valentine's Day is called Ystävänpäivä which translates into "Friend's day". As the name says, this day is more about remembering all your friends, not only your loved ones."
"Valentine's Day also has regional traditions in the UK. In Norfolk a character called 'Jack' Valentine knocks on the rear door of houses leaving sweets and presents for children." (though to be fair, first I've heard of that!!)
I think the nice bit about being a family is you can pick and choose your own traditions to follow, tbh.