The right thing to do is offer a program to replace the battery. Even more right would be not designing anti-repairability into your products. 🙊

Throttling the processor to extend the life of the phone is a reasonable temporary alternative IF it's transparent and opt-in. Effectively forcibly downgrading the hardware spec of a device I own without even telling me is a serious breach of trust at the very least, no?

I agree the decision may have resulted in less e-waste but, even if so (and assuming all is well-intended), that can't justify hijacking consumer's belongings. That's a dangerous precedent to set.