a) A ton of people over 25 don't "celebrate" a birthday until they're 70 or something and retired and just want to spend time with grandchildren. They just recognise the day and then maybe have a fancy meal but cut off right there. +Once you're over 90 yrs old (otherwise 100), those are milestones.
b) If you're telling people aged 5-12 to eliminate the concept of a birthday then that is actually EXTREMELY cruel. Let the kids enjoy the childhood whilst it lasts with special days for special events before they have to enter the world of adulthood.
c) I don't celebrate birthdays often; I had no parties for my whole life and nobody cared until recently when they were like "you have to have an 18th". To be fair, between the age of 12-24 you still don't have much going on in your life. But you find that firstly:
c) (1.) Over 18 yrs old - People generally already start to stop caring. It just doesn't become significant until 25 in my opinion.
c) (2.) 13-14 yrs old - What exactly can you do? Not EVERYONE needs a job
The only thing ambiguous is 15-17. And even then you can't be that demanding for no reason. Teenagers would like a good time too.
It just means they shouldn't fuss over it for no reason. Have a small celebration and that's it.
To most people, saying birthdays are useless is like saying Christmas is useless. Because not everyone celebrates Christmas in the religious way. In more simplier terms? No such thing as happiness should exist.
It's not like we're saying oh it's his birthday take a day off school/work. We're saying birthdays shouldn't exist.