How is it out of their control? BA sells the tickets.
Not all children cry, not all adults don't. Once long ago I sat on an AA flight next to a bawling 20-something lady who had broken up with her who-knows-what before boarding. As has been referenced on this thread many, many times - there are a multitude of ways people of all ages can make noise.
BA Cannot ensure you sleep. Get over it.
It's not like the toddler is going to benefit from flying across an ocean and having experiences it won't remember.
No, but its grandparents/great grandparents who cannot fly and won't live forever might miss out on some experiences.